Merge branch 'master' into docking

# Conflicts:
#	examples/imgui_impl_dx10.cpp
#	examples/imgui_impl_dx11.cpp
#	examples/imgui_impl_dx12.cpp
#	examples/imgui_impl_dx9.cpp
#	examples/imgui_impl_opengl2.cpp
#	examples/imgui_impl_opengl3.cpp
#	examples/imgui_impl_vulkan.cpp
#	imgui.cpp

docs/CHANGELOG.txt

@@ -100,6 +100,8 @@ Other changes:
 Breaking Changes:
 - ImDrawList: Fixed rectangles with thick lines (>1.0f) not being as thick as requested. (#2518)
   If you have custom rendering using thick lines, they will appear thicker now.
+- Obsoleted GetContentRegionAvailWidth(), use GetContentRegionAvail().x instead.
+  Kept inline redirection function.
 - Examples: Vulkan: Added MinImageCount/ImageCount fields in ImGui_ImplVulkan_InitInfo, required
   during initialization to specify the number of in-flight image requested by swap chains.
   (was previously a hard #define IMGUI_VK_QUEUED_FRAMES 2). (#2071, #1677) [@nathanvoglsam]
@@ -107,6 +109,11 @@ Breaking Changes:
   on them but it is possible you have!).
 
 Other Changes:
+- ImDrawList: Added ImDrawCallback_ResetRenderState, a special ImDrawList::AddCallback() value
+  to request the renderer back-end to reset its render state. (#2037, #1639, #2452)
+  Examples: Added support for ImDrawCallback_ResetRenderState in all renderer back-ends. Each
+  renderer code setting up initial render state has been moved to a function so it could be
+  called at the start of rendering and when a ResetRenderState is requested. [@ocornut, @bear24rw]
 - InputText: Fixed selection background starts rendering one frame after the cursor movement
   when first transitioning from no-selection to has-selection. (Bug in 1.69) (#2436) [@Nazg-Gul]
 - InputText: Work-around for buggy standard libraries where isprint('\t') returns true. (#2467, #1336)
@@ -139,6 +146,8 @@ Other Changes:
 - Separator: Declare its thickness (1.0f) to the layout, making items around separator more symmetrical.
 - Combo, Slider, Scrollbar: Improve rendering in situation when there's only a few pixels available (<3 pixels).
 - Nav: Fixed Drag/Slider functions going into text input mode when keyboard CTRL is held while pressing NavActivate.
+- Drag and Drop: Fixed drag source with ImGuiDragDropFlags_SourceAllowNullID and null ID from receiving click
+  regardless of being covered by another window (it didn't honor correct hovering rules). (#2521)
 - ImDrawList: Improved algorithm for mitre joints on thick lines, preserving correct thickness up to 90 degrees
   angles, also faster to output. (#2518) [@rmitton]
 - Misc: Added IM_MALLOC/IM_FREE macros mimicking IM_NEW/IM_DELETE so user doesn't need to revert

docs/TODO.txt

@@ -262,6 +262,7 @@ It's mostly a bunch of personal notes, probably incomplete. Feel free to query i
  - filters: handle wild-cards (with implicit leading/trailing *), reg-exprs
  - filters: fuzzy matches (may use code at blog.forrestthewoods.com/4cffeed33fdb)
 
+ - drag and drop: drag tooltip hovering over source widget with IsItemHovered/SetTooltip flickers.
  - drag and drop: releasing a drop shows the "..." tooltip for one frame - since e13e598 (#1725)
  - drag and drop: have some way to know when a drag begin from BeginDragDropSource() pov.
  - drag and drop: allow preview tooltip to be submitted from a different place than the drag source. (#1725)

examples/imgui_impl_allegro5.cpp

@@ -15,6 +15,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2019-04-30: Renderer: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2018-11-30: Platform: Added touchscreen support.
 //  2018-11-30: Misc: Setting up io.BackendPlatformName/io.BackendRendererName so they can be displayed in the About Window.
 //  2018-06-13: Platform: Added clipboard support (from Allegro 5.1.12).
@@ -60,23 +61,9 @@ struct ImDrawVertAllegro
     ALLEGRO_COLOR col;
 };
 
-// Render function.
-// (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
-void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
+static void ImGui_ImplAllegro5_SetupRenderState(ImDrawData* draw_data)
 {
-    // Avoid rendering when minimized
-    if (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f)
-        return;
-
-    // Backup Allegro state that will be modified
-    ALLEGRO_TRANSFORM last_transform = *al_get_current_transform();
-    ALLEGRO_TRANSFORM last_projection_transform = *al_get_current_projection_transform();
-    int last_clip_x, last_clip_y, last_clip_w, last_clip_h;
-    al_get_clipping_rectangle(&last_clip_x, &last_clip_y, &last_clip_w, &last_clip_h);
-    int last_blender_op, last_blender_src, last_blender_dst;
-    al_get_blender(&last_blender_op, &last_blender_src, &last_blender_dst);
-
-    // Setup render state
+    // Setup blending
     al_set_blender(ALLEGRO_ADD, ALLEGRO_ALPHA, ALLEGRO_INVERSE_ALPHA);
 
     // Setup orthographic projection matrix
@@ -92,7 +79,28 @@ void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
         al_orthographic_transform(&transform, L, T, 1.0f, R, B, -1.0f);
         al_use_projection_transform(&transform);
     }
+}
+
+// Render function.
+// (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
+void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
+{
+    // Avoid rendering when minimized
+    if (draw_data->DisplaySize.x <= 0.0f || draw_data->DisplaySize.y <= 0.0f)
+        return;
+
+    // Backup Allegro state that will be modified
+    ALLEGRO_TRANSFORM last_transform = *al_get_current_transform();
+    ALLEGRO_TRANSFORM last_projection_transform = *al_get_current_projection_transform();
+    int last_clip_x, last_clip_y, last_clip_w, last_clip_h;
+    al_get_clipping_rectangle(&last_clip_x, &last_clip_y, &last_clip_w, &last_clip_h);
+    int last_blender_op, last_blender_src, last_blender_dst;
+    al_get_blender(&last_blender_op, &last_blender_src, &last_blender_dst);
+
+    // Setup desired render state
+    ImGui_ImplAllegro5_SetupRenderState(draw_data);
 
+    // Render command lists
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
         const ImDrawList* cmd_list = draw_data->CmdLists[n];
@@ -135,10 +143,16 @@ void ImGui_ImplAllegro5_RenderDrawData(ImDrawData* draw_data)
             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
             if (pcmd->UserCallback)
             {
-                pcmd->UserCallback(cmd_list, pcmd);
+                // User callback, registered via ImDrawList::AddCallback()
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    ImGui_ImplAllegro5_SetupRenderState(draw_data);
+                else
+                    pcmd->UserCallback(cmd_list, pcmd);
             }
             else
             {
+                // Draw
                 ALLEGRO_BITMAP* texture = (ALLEGRO_BITMAP*)pcmd->TextureId;
                 al_set_clipping_rectangle(pcmd->ClipRect.x - clip_off.x, pcmd->ClipRect.y - clip_off.y, pcmd->ClipRect.z - pcmd->ClipRect.x, pcmd->ClipRect.w - pcmd->ClipRect.y);
                 al_draw_prim(&vertices[0], g_VertexDecl, texture, idx_offset, idx_offset + pcmd->ElemCount, ALLEGRO_PRIM_TRIANGLE_LIST);

examples/imgui_impl_dx10.cpp

@@ -12,6 +12,7 @@
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
 //  2018-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2019-04-30: DirectX10: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2018-12-03: Misc: Added #pragma comment statement to automatically link with d3dcompiler.lib when using D3DCompile().
 //  2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window.
 //  2018-07-13: DirectX10: Fixed unreleased resources in Init and Shutdown functions.
@@ -61,6 +62,37 @@ struct VERTEX_CONSTANT_BUFFER
 static void ImGui_ImplDX10_InitPlatformInterface();
 static void ImGui_ImplDX10_ShutdownPlatformInterface();
 
+static void ImGui_ImplDX10_SetupRenderState(ImDrawData* draw_data, ID3D10Device* ctx)
+{
+    // Setup viewport
+    D3D10_VIEWPORT vp;
+    memset(&vp, 0, sizeof(D3D10_VIEWPORT));
+    vp.Width = (UINT)draw_data->DisplaySize.x;
+    vp.Height = (UINT)draw_data->DisplaySize.y;
+    vp.MinDepth = 0.0f;
+    vp.MaxDepth = 1.0f;
+    vp.TopLeftX = vp.TopLeftY = 0;
+    ctx->RSSetViewports(1, &vp);
+
+    // Bind shader and vertex buffers
+    unsigned int stride = sizeof(ImDrawVert);
+    unsigned int offset = 0;
+    ctx->IASetInputLayout(g_pInputLayout);
+    ctx->IASetVertexBuffers(0, 1, &g_pVB, &stride, &offset);
+    ctx->IASetIndexBuffer(g_pIB, sizeof(ImDrawIdx) == 2 ? DXGI_FORMAT_R16_UINT : DXGI_FORMAT_R32_UINT, 0);
+    ctx->IASetPrimitiveTopology(D3D10_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
+    ctx->VSSetShader(g_pVertexShader);
+    ctx->VSSetConstantBuffers(0, 1, &g_pVertexConstantBuffer);
+    ctx->PSSetShader(g_pPixelShader);
+    ctx->PSSetSamplers(0, 1, &g_pFontSampler);
+
+    // Setup render state
+    const float blend_factor[4] = { 0.f, 0.f, 0.f, 0.f };
+    ctx->OMSetBlendState(g_pBlendState, blend_factor, 0xffffffff);
+    ctx->OMSetDepthStencilState(g_pDepthStencilState, 0);
+    ctx->RSSetState(g_pRasterizerState);
+}
+
 // Render function
 // (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
 void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
@@ -178,33 +210,8 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
     ctx->IAGetVertexBuffers(0, 1, &old.VertexBuffer, &old.VertexBufferStride, &old.VertexBufferOffset);
     ctx->IAGetInputLayout(&old.InputLayout);
 
-    // Setup viewport
-    D3D10_VIEWPORT vp;
-    memset(&vp, 0, sizeof(D3D10_VIEWPORT));
-    vp.Width = (UINT)draw_data->DisplaySize.x;
-    vp.Height = (UINT)draw_data->DisplaySize.y;
-    vp.MinDepth = 0.0f;
-    vp.MaxDepth = 1.0f;
-    vp.TopLeftX = vp.TopLeftY = 0;
-    ctx->RSSetViewports(1, &vp);
-
-    // Bind shader and vertex buffers
-    unsigned int stride = sizeof(ImDrawVert);
-    unsigned int offset = 0;
-    ctx->IASetInputLayout(g_pInputLayout);
-    ctx->IASetVertexBuffers(0, 1, &g_pVB, &stride, &offset);
-    ctx->IASetIndexBuffer(g_pIB, sizeof(ImDrawIdx) == 2 ? DXGI_FORMAT_R16_UINT : DXGI_FORMAT_R32_UINT, 0);
-    ctx->IASetPrimitiveTopology(D3D10_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
-    ctx->VSSetShader(g_pVertexShader);
-    ctx->VSSetConstantBuffers(0, 1, &g_pVertexConstantBuffer);
-    ctx->PSSetShader(g_pPixelShader);
-    ctx->PSSetSamplers(0, 1, &g_pFontSampler);
-
-    // Setup render state
-    const float blend_factor[4] = { 0.f, 0.f, 0.f, 0.f };
-    ctx->OMSetBlendState(g_pBlendState, blend_factor, 0xffffffff);
-    ctx->OMSetDepthStencilState(g_pDepthStencilState, 0);
-    ctx->RSSetState(g_pRasterizerState);
+    // Setup desired DX state
+    ImGui_ImplDX10_SetupRenderState(draw_data, ctx);
 
     // Render command lists
     int vtx_offset = 0;
@@ -218,8 +225,12 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
             if (pcmd->UserCallback)
             {
-                // User callback (registered via ImDrawList::AddCallback)
-                pcmd->UserCallback(cmd_list, pcmd);
+                // User callback, registered via ImDrawList::AddCallback()
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    ImGui_ImplDX10_SetupRenderState(draw_data, ctx);
+                else
+                    pcmd->UserCallback(cmd_list, pcmd);
             }
             else
             {

examples/imgui_impl_dx11.cpp

@@ -12,6 +12,7 @@
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
 //  2018-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2019-04-30: DirectX11: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2018-12-03: Misc: Added #pragma comment statement to automatically link with d3dcompiler.lib when using D3DCompile().
 //  2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window.
 //  2018-08-01: DirectX11: Querying for IDXGIFactory instead of IDXGIFactory1 to increase compatibility.
@@ -61,6 +62,38 @@ struct VERTEX_CONSTANT_BUFFER
 static void ImGui_ImplDX11_InitPlatformInterface();
 static void ImGui_ImplDX11_ShutdownPlatformInterface();
 
+static void ImGui_ImplDX11_SetupRenderState(ImDrawData* draw_data, ID3D11DeviceContext* ctx)
+{
+    // Setup viewport
+    D3D11_VIEWPORT vp;
+    memset(&vp, 0, sizeof(D3D11_VIEWPORT));
+    vp.Width = draw_data->DisplaySize.x;
+    vp.Height = draw_data->DisplaySize.y;
+    vp.MinDepth = 0.0f;
+    vp.MaxDepth = 1.0f;
+    vp.TopLeftX = vp.TopLeftY = 0;
+    ctx->RSSetViewports(1, &vp);
+
+    // Setup shader and vertex buffers
+    unsigned int stride = sizeof(ImDrawVert);
+    unsigned int offset = 0;
+    ctx->IASetInputLayout(g_pInputLayout);
+    ctx->IASetVertexBuffers(0, 1, &g_pVB, &stride, &offset);
+    ctx->IASetIndexBuffer(g_pIB, sizeof(ImDrawIdx) == 2 ? DXGI_FORMAT_R16_UINT : DXGI_FORMAT_R32_UINT, 0);
+    ctx->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
+    ctx->VSSetShader(g_pVertexShader, NULL, 0);
+    ctx->VSSetConstantBuffers(0, 1, &g_pVertexConstantBuffer);
+    ctx->PSSetShader(g_pPixelShader, NULL, 0);
+    ctx->PSSetSamplers(0, 1, &g_pFontSampler);
+
+    // Setup blend state
+    const float blend_factor[4] = { 0.f, 0.f, 0.f, 0.f };
+    ctx->OMSetBlendState(g_pBlendState, blend_factor, 0xffffffff);
+    ctx->OMSetDepthStencilState(g_pDepthStencilState, 0);
+    ctx->RSSetState(g_pRasterizerState);
+}
+>>>>>>> master
+
 // Render function
 // (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
 void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
@@ -183,33 +216,8 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
     ctx->IAGetVertexBuffers(0, 1, &old.VertexBuffer, &old.VertexBufferStride, &old.VertexBufferOffset);
     ctx->IAGetInputLayout(&old.InputLayout);
 
-    // Setup viewport
-    D3D11_VIEWPORT vp;
-    memset(&vp, 0, sizeof(D3D11_VIEWPORT));
-    vp.Width =  draw_data->DisplaySize.x;
-    vp.Height = draw_data->DisplaySize.y;
-    vp.MinDepth = 0.0f;
-    vp.MaxDepth = 1.0f;
-    vp.TopLeftX = vp.TopLeftY = 0;
-    ctx->RSSetViewports(1, &vp);
-
-    // Bind shader and vertex buffers
-    unsigned int stride = sizeof(ImDrawVert);
-    unsigned int offset = 0;
-    ctx->IASetInputLayout(g_pInputLayout);
-    ctx->IASetVertexBuffers(0, 1, &g_pVB, &stride, &offset);
-    ctx->IASetIndexBuffer(g_pIB, sizeof(ImDrawIdx) == 2 ? DXGI_FORMAT_R16_UINT : DXGI_FORMAT_R32_UINT, 0);
-    ctx->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
-    ctx->VSSetShader(g_pVertexShader, NULL, 0);
-    ctx->VSSetConstantBuffers(0, 1, &g_pVertexConstantBuffer);
-    ctx->PSSetShader(g_pPixelShader, NULL, 0);
-    ctx->PSSetSamplers(0, 1, &g_pFontSampler);
-
-    // Setup render state
-    const float blend_factor[4] = { 0.f, 0.f, 0.f, 0.f };
-    ctx->OMSetBlendState(g_pBlendState, blend_factor, 0xffffffff);
-    ctx->OMSetDepthStencilState(g_pDepthStencilState, 0);
-    ctx->RSSetState(g_pRasterizerState);
+    // Setup desired DX state
+    ImGui_ImplDX11_SetupRenderState(draw_data, ctx);
 
     // Render command lists
     int vtx_offset = 0;
@@ -221,10 +229,14 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
         for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
-            if (pcmd->UserCallback)
+            if (pcmd->UserCallback != NULL)
             {
-                // User callback (registered via ImDrawList::AddCallback)
-                pcmd->UserCallback(cmd_list, pcmd);
+                // User callback, registered via ImDrawList::AddCallback()
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    ImGui_ImplDX11_SetupRenderState(draw_data, ctx);
+                else
+                    pcmd->UserCallback(cmd_list, pcmd);
             }
             else
             {

examples/imgui_impl_dx12.cpp

@@ -12,6 +12,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2019-04-30: DirectX12: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2019-03-29: Misc: Various minor tidying up.
 //  2018-12-03: Misc: Added #pragma comment statement to automatically link with d3dcompiler.lib when using D3DCompile().
 //  2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window.
@@ -62,6 +63,61 @@ struct VERTEX_CONSTANT_BUFFER
 static void ImGui_ImplDX12_InitPlatformInterface();
 static void ImGui_ImplDX12_ShutdownPlatformInterface();
 
+static void ImGui_ImplDX12_SetupRenderState(ImDrawData* draw_data, ID3D12GraphicsCommandList* ctx, FrameResources* fr)
+{
+    // Setup orthographic projection matrix into our constant buffer
+    // Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right).
+    VERTEX_CONSTANT_BUFFER vertex_constant_buffer;
+    {
+        float L = draw_data->DisplayPos.x;
+        float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
+        float T = draw_data->DisplayPos.y;
+        float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
+        float mvp[4][4] =
+        {
+            { 2.0f/(R-L),   0.0f,           0.0f,       0.0f },
+            { 0.0f,         2.0f/(T-B),     0.0f,       0.0f },
+            { 0.0f,         0.0f,           0.5f,       0.0f },
+            { (R+L)/(L-R),  (T+B)/(B-T),    0.5f,       1.0f },
+        };
+        memcpy(&vertex_constant_buffer.mvp, mvp, sizeof(mvp));
+    }
+
+    // Setup viewport
+    D3D12_VIEWPORT vp;
+    memset(&vp, 0, sizeof(D3D12_VIEWPORT));
+    vp.Width = draw_data->DisplaySize.x;
+    vp.Height = draw_data->DisplaySize.y;
+    vp.MinDepth = 0.0f;
+    vp.MaxDepth = 1.0f;
+    vp.TopLeftX = vp.TopLeftY = 0.0f;
+    ctx->RSSetViewports(1, &vp);
+
+    // Bind shader and vertex buffers
+    unsigned int stride = sizeof(ImDrawVert);
+    unsigned int offset = 0;
+    D3D12_VERTEX_BUFFER_VIEW vbv;
+    memset(&vbv, 0, sizeof(D3D12_VERTEX_BUFFER_VIEW));
+    vbv.BufferLocation = fr->VertexBuffer->GetGPUVirtualAddress() + offset;
+    vbv.SizeInBytes = fr->VertexBufferSize * stride;
+    vbv.StrideInBytes = stride;
+    ctx->IASetVertexBuffers(0, 1, &vbv);
+    D3D12_INDEX_BUFFER_VIEW ibv;
+    memset(&ibv, 0, sizeof(D3D12_INDEX_BUFFER_VIEW));
+    ibv.BufferLocation = fr->IndexBuffer->GetGPUVirtualAddress();
+    ibv.SizeInBytes = fr->IndexBufferSize * sizeof(ImDrawIdx);
+    ibv.Format = sizeof(ImDrawIdx) == 2 ? DXGI_FORMAT_R16_UINT : DXGI_FORMAT_R32_UINT;
+    ctx->IASetIndexBuffer(&ibv);
+    ctx->IASetPrimitiveTopology(D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
+    ctx->SetPipelineState(g_pPipelineState);
+    ctx->SetGraphicsRootSignature(g_pRootSignature);
+    ctx->SetGraphicsRoot32BitConstants(0, 16, &vertex_constant_buffer, 0);
+
+    // Setup blend factor
+    const float blend_factor[4] = { 0.f, 0.f, 0.f, 0.f };
+    ctx->OMSetBlendFactor(blend_factor);
+}
+
 // Render function
 // (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
 void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandList* ctx)
@@ -144,57 +200,8 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
     fr->VertexBuffer->Unmap(0, &range);
     fr->IndexBuffer->Unmap(0, &range);
 
-    // Setup orthographic projection matrix into our constant buffer
-    // Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is (0,0) for single viewport apps.
-    VERTEX_CONSTANT_BUFFER vertex_constant_buffer;
-    {
-        float L = draw_data->DisplayPos.x;
-        float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
-        float T = draw_data->DisplayPos.y;
-        float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
-        float mvp[4][4] =
-        {
-            { 2.0f/(R-L),   0.0f,           0.0f,       0.0f },
-            { 0.0f,         2.0f/(T-B),     0.0f,       0.0f },
-            { 0.0f,         0.0f,           0.5f,       0.0f },
-            { (R+L)/(L-R),  (T+B)/(B-T),    0.5f,       1.0f },
-        };
-        memcpy(&vertex_constant_buffer.mvp, mvp, sizeof(mvp));
-    }
-
-    // Setup viewport
-    D3D12_VIEWPORT vp;
-    memset(&vp, 0, sizeof(D3D12_VIEWPORT));
-    vp.Width = draw_data->DisplaySize.x;
-    vp.Height = draw_data->DisplaySize.y;
-    vp.MinDepth = 0.0f;
-    vp.MaxDepth = 1.0f;
-    vp.TopLeftX = vp.TopLeftY = 0.0f;
-    ctx->RSSetViewports(1, &vp);
-
-    // Bind shader and vertex buffers
-    unsigned int stride = sizeof(ImDrawVert);
-    unsigned int offset = 0;
-    D3D12_VERTEX_BUFFER_VIEW vbv;
-    memset(&vbv, 0, sizeof(D3D12_VERTEX_BUFFER_VIEW));
-    vbv.BufferLocation = fr->VertexBuffer->GetGPUVirtualAddress() + offset;
-    vbv.SizeInBytes = fr->VertexBufferSize * stride;
-    vbv.StrideInBytes = stride;
-    ctx->IASetVertexBuffers(0, 1, &vbv);
-    D3D12_INDEX_BUFFER_VIEW ibv;
-    memset(&ibv, 0, sizeof(D3D12_INDEX_BUFFER_VIEW));
-    ibv.BufferLocation = fr->IndexBuffer->GetGPUVirtualAddress();
-    ibv.SizeInBytes = fr->IndexBufferSize * sizeof(ImDrawIdx);
-    ibv.Format = sizeof(ImDrawIdx) == 2 ? DXGI_FORMAT_R16_UINT : DXGI_FORMAT_R32_UINT;
-    ctx->IASetIndexBuffer(&ibv);
-    ctx->IASetPrimitiveTopology(D3D_PRIMITIVE_TOPOLOGY_TRIANGLELIST);
-    ctx->SetPipelineState(g_pPipelineState);
-    ctx->SetGraphicsRootSignature(g_pRootSignature);
-    ctx->SetGraphicsRoot32BitConstants(0, 16, &vertex_constant_buffer, 0);
-
-    // Setup blend factor
-    const float blend_factor[4] = { 0.f, 0.f, 0.f, 0.f };
-    ctx->OMSetBlendFactor(blend_factor);
+    // Setup desired DX state
+    ImGui_ImplDX12_SetupRenderState(draw_data, ctx, fr);
 
     // Render command lists
     int vtx_offset = 0;
@@ -206,10 +213,14 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
         for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
-            if (pcmd->UserCallback)
+            if (pcmd->UserCallback != NULL)
             {
-                // User callback (registered via ImDrawList::AddCallback)
-                pcmd->UserCallback(cmd_list, pcmd);
+                // User callback, registered via ImDrawList::AddCallback()
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    ImGui_ImplDX12_SetupRenderState(draw_data, ctx, fr);
+                else
+                    pcmd->UserCallback(cmd_list, pcmd);
             }
             else
             {

examples/imgui_impl_dx9.cpp

@@ -12,6 +12,7 @@
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
 //  2018-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2019-04-30: DirectX9: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2019-03-29: Misc: Fixed erroneous assert in ImGui_ImplDX9_InvalidateDeviceObjects().
 //  2019-01-16: Misc: Disabled fog before drawing UI's. Fixes issue #2288.
 //  2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window.
@@ -48,6 +49,62 @@ struct CUSTOMVERTEX
 static void ImGui_ImplDX9_InitPlatformInterface();
 static void ImGui_ImplDX9_ShutdownPlatformInterface();
 
+static void ImGui_ImplDX9_SetupRenderState(ImDrawData* draw_data)
+{
+    // Setup viewport
+    D3DVIEWPORT9 vp;
+    vp.X = vp.Y = 0;
+    vp.Width = (DWORD)draw_data->DisplaySize.x;
+    vp.Height = (DWORD)draw_data->DisplaySize.y;
+    vp.MinZ = 0.0f;
+    vp.MaxZ = 1.0f;
+    g_pd3dDevice->SetViewport(&vp);
+
+    // Setup render state: fixed-pipeline, alpha-blending, no face culling, no depth testing, shade mode (for gradient)
+    g_pd3dDevice->SetPixelShader(NULL);
+    g_pd3dDevice->SetVertexShader(NULL);
+    g_pd3dDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);
+    g_pd3dDevice->SetRenderState(D3DRS_LIGHTING, false);
+    g_pd3dDevice->SetRenderState(D3DRS_ZENABLE, false);
+    g_pd3dDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, true);
+    g_pd3dDevice->SetRenderState(D3DRS_ALPHATESTENABLE, false);
+    g_pd3dDevice->SetRenderState(D3DRS_BLENDOP, D3DBLENDOP_ADD);
+    g_pd3dDevice->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
+    g_pd3dDevice->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);
+    g_pd3dDevice->SetRenderState(D3DRS_SCISSORTESTENABLE, true);
+    g_pd3dDevice->SetRenderState(D3DRS_SHADEMODE, D3DSHADE_GOURAUD);
+    g_pd3dDevice->SetRenderState(D3DRS_FOGENABLE, false);
+    g_pd3dDevice->SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_MODULATE);
+    g_pd3dDevice->SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TEXTURE);
+    g_pd3dDevice->SetTextureStageState(0, D3DTSS_COLORARG2, D3DTA_DIFFUSE);
+    g_pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_MODULATE);
+    g_pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAARG1, D3DTA_TEXTURE);
+    g_pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAARG2, D3DTA_DIFFUSE);
+    g_pd3dDevice->SetSamplerState(0, D3DSAMP_MINFILTER, D3DTEXF_LINEAR);
+    g_pd3dDevice->SetSamplerState(0, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR);
+
+    // Setup orthographic projection matrix
+    // Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is (0,0) for single viewport apps.
+    // Being agnostic of whether <d3dx9.h> or <DirectXMath.h> can be used, we aren't relying on D3DXMatrixIdentity()/D3DXMatrixOrthoOffCenterLH() or DirectX::XMMatrixIdentity()/DirectX::XMMatrixOrthographicOffCenterLH()
+    {
+        float L = draw_data->DisplayPos.x + 0.5f;
+        float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x + 0.5f;
+        float T = draw_data->DisplayPos.y + 0.5f;
+        float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y + 0.5f;
+        D3DMATRIX mat_identity = { { { 1.0f, 0.0f, 0.0f, 0.0f,  0.0f, 1.0f, 0.0f, 0.0f,  0.0f, 0.0f, 1.0f, 0.0f,  0.0f, 0.0f, 0.0f, 1.0f } } };
+        D3DMATRIX mat_projection =
+        { { {
+            2.0f/(R-L),   0.0f,         0.0f,  0.0f,
+            0.0f,         2.0f/(T-B),   0.0f,  0.0f,
+            0.0f,         0.0f,         0.5f,  0.0f,
+            (L+R)/(L-R),  (T+B)/(B-T),  0.5f,  1.0f
+        } } };
+        g_pd3dDevice->SetTransform(D3DTS_WORLD, &mat_identity);
+        g_pd3dDevice->SetTransform(D3DTS_VIEW, &mat_identity);
+        g_pd3dDevice->SetTransform(D3DTS_PROJECTION, &mat_projection);
+    }
+}
+
 // Render function.
 // (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
 void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
@@ -117,58 +174,8 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
     g_pd3dDevice->SetIndices(g_pIB);
     g_pd3dDevice->SetFVF(D3DFVF_CUSTOMVERTEX);
 
-    // Setup viewport
-    D3DVIEWPORT9 vp;
-    vp.X = vp.Y = 0;
-    vp.Width = (DWORD)draw_data->DisplaySize.x;
-    vp.Height = (DWORD)draw_data->DisplaySize.y;
-    vp.MinZ = 0.0f;
-    vp.MaxZ = 1.0f;
-    g_pd3dDevice->SetViewport(&vp);
-
-    // Setup render state: fixed-pipeline, alpha-blending, no face culling, no depth testing, shade mode (for gradient)
-    g_pd3dDevice->SetPixelShader(NULL);
-    g_pd3dDevice->SetVertexShader(NULL);
-    g_pd3dDevice->SetRenderState(D3DRS_CULLMODE, D3DCULL_NONE);
-    g_pd3dDevice->SetRenderState(D3DRS_LIGHTING, false);
-    g_pd3dDevice->SetRenderState(D3DRS_ZENABLE, false);
-    g_pd3dDevice->SetRenderState(D3DRS_ALPHABLENDENABLE, true);
-    g_pd3dDevice->SetRenderState(D3DRS_ALPHATESTENABLE, false);
-    g_pd3dDevice->SetRenderState(D3DRS_BLENDOP, D3DBLENDOP_ADD);
-    g_pd3dDevice->SetRenderState(D3DRS_SRCBLEND, D3DBLEND_SRCALPHA);
-    g_pd3dDevice->SetRenderState(D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA);
-    g_pd3dDevice->SetRenderState(D3DRS_SCISSORTESTENABLE, true);
-    g_pd3dDevice->SetRenderState(D3DRS_SHADEMODE, D3DSHADE_GOURAUD);
-    g_pd3dDevice->SetRenderState(D3DRS_FOGENABLE, false);
-    g_pd3dDevice->SetTextureStageState(0, D3DTSS_COLOROP, D3DTOP_MODULATE);
-    g_pd3dDevice->SetTextureStageState(0, D3DTSS_COLORARG1, D3DTA_TEXTURE);
-    g_pd3dDevice->SetTextureStageState(0, D3DTSS_COLORARG2, D3DTA_DIFFUSE);
-    g_pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAOP, D3DTOP_MODULATE);
-    g_pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAARG1, D3DTA_TEXTURE);
-    g_pd3dDevice->SetTextureStageState(0, D3DTSS_ALPHAARG2, D3DTA_DIFFUSE);
-    g_pd3dDevice->SetSamplerState(0, D3DSAMP_MINFILTER, D3DTEXF_LINEAR);
-    g_pd3dDevice->SetSamplerState(0, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR);
-
-    // Setup orthographic projection matrix
-    // Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is (0,0) for single viewport apps.
-    // Being agnostic of whether <d3dx9.h> or <DirectXMath.h> can be used, we aren't relying on D3DXMatrixIdentity()/D3DXMatrixOrthoOffCenterLH() or DirectX::XMMatrixIdentity()/DirectX::XMMatrixOrthographicOffCenterLH()
-    {
-        float L = draw_data->DisplayPos.x + 0.5f;
-        float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x + 0.5f;
-        float T = draw_data->DisplayPos.y + 0.5f;
-        float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y + 0.5f;
-        D3DMATRIX mat_identity = { { { 1.0f, 0.0f, 0.0f, 0.0f,  0.0f, 1.0f, 0.0f, 0.0f,  0.0f, 0.0f, 1.0f, 0.0f,  0.0f, 0.0f, 0.0f, 1.0f } } };
-        D3DMATRIX mat_projection =
-        { { {
-            2.0f/(R-L),   0.0f,         0.0f,  0.0f,
-            0.0f,         2.0f/(T-B),   0.0f,  0.0f,
-            0.0f,         0.0f,         0.5f,  0.0f,
-            (L+R)/(L-R),  (T+B)/(B-T),  0.5f,  1.0f
-        } } };
-        g_pd3dDevice->SetTransform(D3DTS_WORLD, &mat_identity);
-        g_pd3dDevice->SetTransform(D3DTS_VIEW, &mat_identity);
-        g_pd3dDevice->SetTransform(D3DTS_PROJECTION, &mat_projection);
-    }
+    // Setup desired DX state
+    ImGui_ImplDX9_SetupRenderState(draw_data);
 
     // Render command lists
     int vtx_offset = 0;
@@ -180,9 +187,14 @@ void ImGui_ImplDX9_RenderDrawData(ImDrawData* draw_data)
         for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
-            if (pcmd->UserCallback)
+            if (pcmd->UserCallback != NULL)
             {
-                pcmd->UserCallback(cmd_list, pcmd);
+                // User callback, registered via ImDrawList::AddCallback()
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    ImGui_ImplDX9_SetupRenderState(draw_data);
+                else
+                    pcmd->UserCallback(cmd_list, pcmd);
             }
             else
             {

examples/imgui_impl_metal.mm

@@ -12,6 +12,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2019-04-30: Metal: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2019-02-11: Metal: Projecting clipping rectangles correctly using draw_data->FramebufferScale to allow multi-viewports for retina display.
 //  2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window.
 //  2018-07-05: Metal: Added new Metal backend implementation.
@@ -58,6 +59,12 @@
 - (void)enqueueReusableBuffer:(MetalBuffer *)buffer;
 - (id<MTLRenderPipelineState>)renderPipelineStateForFrameAndDevice:(id<MTLDevice>)device;
 - (void)emptyRenderPipelineStateCache;
+- (void)setupRenderState:(ImDrawData *)drawData
+           commandBuffer:(id<MTLCommandBuffer>)commandBuffer
+          commandEncoder:(id<MTLRenderCommandEncoder>)commandEncoder
+     renderPipelineState:(id<MTLRenderPipelineState>)renderPipelineState
+            vertexBuffer:(MetalBuffer *)vertexBuffer
+      vertexBufferOffset:(size_t)vertexBufferOffset;
 - (void)renderDrawData:(ImDrawData *)drawData
          commandBuffer:(id<MTLCommandBuffer>)commandBuffer
         commandEncoder:(id<MTLRenderCommandEncoder>)commandEncoder;
@@ -399,16 +406,13 @@ void ImGui_ImplMetal_DestroyDeviceObjects()
     [self.renderPipelineStateCache removeAllObjects];
 }
 
-- (void)renderDrawData:(ImDrawData *)drawData
-         commandBuffer:(id<MTLCommandBuffer>)commandBuffer
-        commandEncoder:(id<MTLRenderCommandEncoder>)commandEncoder
+- (void)setupRenderState:(ImDrawData *)drawData
+           commandBuffer:(id<MTLCommandBuffer>)commandBuffer
+          commandEncoder:(id<MTLRenderCommandEncoder>)commandEncoder
+     renderPipelineState:(id<MTLRenderPipelineState>)renderPipelineState
+            vertexBuffer:(MetalBuffer *)vertexBuffer
+      vertexBufferOffset:(size_t)vertexBufferOffset
 {
-    // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
-    int fb_width = (int)(drawData->DisplaySize.x * drawData->FramebufferScale.x);
-    int fb_height = (int)(drawData->DisplaySize.y * drawData->FramebufferScale.y);
-    if (fb_width <= 0 || fb_height <= 0 || drawData->CmdListsCount == 0)
-        return;
-
     [commandEncoder setCullMode:MTLCullModeNone];
     [commandEncoder setDepthStencilState:g_sharedMetalContext.depthStencilState];
 
@@ -419,12 +423,13 @@ void ImGui_ImplMetal_DestroyDeviceObjects()
     {
         .originX = 0.0,
         .originY = 0.0,
-        .width = double(fb_width),
-        .height = double(fb_height),
+        .width = (double)(drawData->DisplaySize.x * drawData->FramebufferScale.x),
+        .height = (double)(drawData->DisplaySize.y * drawData->FramebufferScale.y),
         .znear = 0.0,
         .zfar = 1.0
     };
     [commandEncoder setViewport:viewport];
+
     float L = drawData->DisplayPos.x;
     float R = drawData->DisplayPos.x + drawData->DisplaySize.x;
     float T = drawData->DisplayPos.y;
@@ -438,18 +443,32 @@ void ImGui_ImplMetal_DestroyDeviceObjects()
         { 0.0f,         0.0f,        1/(F-N),   0.0f },
         { (R+L)/(L-R),  (T+B)/(B-T), N/(F-N),   1.0f },
     };
-
     [commandEncoder setVertexBytes:&ortho_projection length:sizeof(ortho_projection) atIndex:1];
 
+    [commandEncoder setRenderPipelineState:renderPipelineState];
+
+    [commandEncoder setVertexBuffer:vertexBuffer.buffer offset:0 atIndex:0];
+    [commandEncoder setVertexBufferOffset:vertexBufferOffset atIndex:0];
+}
+
+- (void)renderDrawData:(ImDrawData *)drawData
+         commandBuffer:(id<MTLCommandBuffer>)commandBuffer
+        commandEncoder:(id<MTLRenderCommandEncoder>)commandEncoder
+{
+    // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
+    int fb_width = (int)(drawData->DisplaySize.x * drawData->FramebufferScale.x);
+    int fb_height = (int)(drawData->DisplaySize.y * drawData->FramebufferScale.y);
+    if (fb_width <= 0 || fb_height <= 0 || drawData->CmdListsCount == 0)
+        return;
+
+    id<MTLRenderPipelineState> renderPipelineState = [self renderPipelineStateForFrameAndDevice:commandBuffer.device];
+
     size_t vertexBufferLength = drawData->TotalVtxCount * sizeof(ImDrawVert);
     size_t indexBufferLength = drawData->TotalIdxCount * sizeof(ImDrawIdx);
     MetalBuffer* vertexBuffer = [self dequeueReusableBufferOfLength:vertexBufferLength device:commandBuffer.device];
     MetalBuffer* indexBuffer = [self dequeueReusableBufferOfLength:indexBufferLength device:commandBuffer.device];
 
-    id<MTLRenderPipelineState> renderPipelineState = [self renderPipelineStateForFrameAndDevice:commandBuffer.device];
-    [commandEncoder setRenderPipelineState:renderPipelineState];
-
-    [commandEncoder setVertexBuffer:vertexBuffer.buffer offset:0 atIndex:0];
+    [self setupRenderState:drawData commandBuffer:commandBuffer commandEncoder:commandEncoder renderPipelineState:renderPipelineState vertexBuffer:vertexBuffer vertexBufferOffset:0];
 
     // Will project scissor/clipping rectangles into framebuffer space
     ImVec2 clip_off = drawData->DisplayPos;         // (0,0) unless using multi-viewports
@@ -473,8 +492,12 @@ void ImGui_ImplMetal_DestroyDeviceObjects()
             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
             if (pcmd->UserCallback)
             {
-                // User callback (registered via ImDrawList::AddCallback)
-                pcmd->UserCallback(cmd_list, pcmd);
+                // User callback, registered via ImDrawList::AddCallback()
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    [self setupRenderState:drawData commandBuffer:commandBuffer commandEncoder:commandEncoder renderPipelineState:renderPipelineState vertexBuffer:vertexBuffer vertexBufferOffset:vertexBufferOffset];
+                else
+                    pcmd->UserCallback(cmd_list, pcmd);
             }
             else
             {

examples/imgui_impl_opengl2.cpp

@@ -20,6 +20,7 @@
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
 //  2018-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2019-04-30: OpenGL: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2019-02-11: OpenGL: Projecting clipping rectangles correctly using draw_data->FramebufferScale to allow multi-viewports for retina display.
 //  2018-11-30: Misc: Setting up io.BackendRendererName so it can be displayed in the About Window.
 //  2018-08-03: OpenGL: Disabling/restoring GL_LIGHTING and GL_COLOR_MATERIAL to increase compatibility with legacy OpenGL applications.
@@ -83,24 +84,9 @@ void    ImGui_ImplOpenGL2_NewFrame()
         ImGui_ImplOpenGL2_CreateDeviceObjects();
 }
 
-// OpenGL2 Render function.
-// (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
-// Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly, in order to be able to run within any OpenGL engine that doesn't do so.
-void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
+static void ImGui_ImplOpenGL2_SetupRenderState(ImDrawData* draw_data, int fb_width, int fb_height)
 {
-    // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
-    int fb_width = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
-    int fb_height = (int)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
-    if (fb_width == 0 || fb_height == 0)
-        return;
-
-    // We are using the OpenGL fixed pipeline to make the example code simpler to read!
     // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, vertex/texcoord/color pointers, polygon fill.
-    GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
-    GLint last_polygon_mode[2]; glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
-    GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
-    GLint last_scissor_box[4]; glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box);
-    glPushAttrib(GL_ENABLE_BIT | GL_COLOR_BUFFER_BIT | GL_TRANSFORM_BIT);
     glEnable(GL_BLEND);
     glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
     glDisable(GL_CULL_FACE);
@@ -132,6 +118,28 @@ void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
     glMatrixMode(GL_MODELVIEW);
     glPushMatrix();
     glLoadIdentity();
+}
+
+// OpenGL2 Render function.
+// (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
+// Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly, in order to be able to run within any OpenGL engine that doesn't do so.
+void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
+{
+    // Avoid rendering when minimized, scale coordinates for retina displays (screen coordinates != framebuffer coordinates)
+    int fb_width = (int)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
+    int fb_height = (int)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
+    if (fb_width == 0 || fb_height == 0)
+        return;
+
+    // Backup GL state
+    GLint last_texture; glGetIntegerv(GL_TEXTURE_BINDING_2D, &last_texture);
+    GLint last_polygon_mode[2]; glGetIntegerv(GL_POLYGON_MODE, last_polygon_mode);
+    GLint last_viewport[4]; glGetIntegerv(GL_VIEWPORT, last_viewport);
+    GLint last_scissor_box[4]; glGetIntegerv(GL_SCISSOR_BOX, last_scissor_box);
+    glPushAttrib(GL_ENABLE_BIT | GL_COLOR_BUFFER_BIT | GL_TRANSFORM_BIT);
+
+    // Setup desired GL state
+    ImGui_ImplOpenGL2_SetupRenderState(draw_data, fb_width, fb_height);
 
     // Will project scissor/clipping rectangles into framebuffer space
     ImVec2 clip_off = draw_data->DisplayPos;         // (0,0) unless using multi-viewports
@@ -152,8 +160,12 @@ void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
             if (pcmd->UserCallback)
             {
-                // User callback (registered via ImDrawList::AddCallback)
-                pcmd->UserCallback(cmd_list, pcmd);
+                // User callback, registered via ImDrawList::AddCallback()
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    ImGui_ImplOpenGL2_SetupRenderState(draw_data, fb_width, fb_height);
+                else
+                    pcmd->UserCallback(cmd_list, pcmd);
             }
             else
             {
@@ -178,7 +190,7 @@ void ImGui_ImplOpenGL2_RenderDrawData(ImDrawData* draw_data)
         }
     }
 
-    // Restore modified state
+    // Restore modified GL state
     glDisableClientState(GL_COLOR_ARRAY);
     glDisableClientState(GL_TEXTURE_COORD_ARRAY);
     glDisableClientState(GL_VERTEX_ARRAY);

examples/imgui_impl_opengl3.cpp

@@ -14,6 +14,7 @@
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
 //  2018-XX-XX: Platform: Added support for multiple windows via the ImGuiPlatformIO interface.
+//  2019-04-30: OpenGL: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
 //  2019-03-29: OpenGL: Not calling glBindBuffer more than necessary in the render loop.
 //  2019-03-15: OpenGL: Added a dummy GL call + comments in ImGui_ImplOpenGL3_Init() to detect uninitialized GL function loaders early.
 //  2019-03-03: OpenGL: Fix support for ES 2.0 (WebGL 1.0).
@@ -162,6 +163,56 @@ void    ImGui_ImplOpenGL3_NewFrame()
         ImGui_ImplOpenGL3_CreateDeviceObjects();
 }
 
+static void ImGui_ImplOpenGL3_SetupRenderState(ImDrawData* draw_data, int fb_width, int fb_height, GLuint vertex_array_object)
+{
+    // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
+    glEnable(GL_BLEND);
+    glBlendEquation(GL_FUNC_ADD);
+    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
+    glDisable(GL_CULL_FACE);
+    glDisable(GL_DEPTH_TEST);
+    glEnable(GL_SCISSOR_TEST);
+#ifdef GL_POLYGON_MODE
+    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+#endif
+
+    // Setup viewport, orthographic projection matrix
+    // Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is (0,0) for single viewport apps.
+    glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
+    float L = draw_data->DisplayPos.x;
+    float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
+    float T = draw_data->DisplayPos.y;
+    float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
+    const float ortho_projection[4][4] =
+    {
+        { 2.0f/(R-L),   0.0f,         0.0f,   0.0f },
+        { 0.0f,         2.0f/(T-B),   0.0f,   0.0f },
+        { 0.0f,         0.0f,        -1.0f,   0.0f },
+        { (R+L)/(L-R),  (T+B)/(B-T),  0.0f,   1.0f },
+    };
+    glUseProgram(g_ShaderHandle);
+    glUniform1i(g_AttribLocationTex, 0);
+    glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
+#ifdef GL_SAMPLER_BINDING
+    glBindSampler(0, 0); // We use combined texture/sampler state. Applications using GL 3.3 may set that otherwise.
+#endif
+
+    (void)vertex_array_object;
+#ifndef IMGUI_IMPL_OPENGL_ES2
+    glBindVertexArray(vertex_array_object);
+#endif
+
+    // Bind vertex/index buffers and setup attributes for ImDrawVert
+    glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
+    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_ElementsHandle);
+    glEnableVertexAttribArray(g_AttribLocationVtxPos);
+    glEnableVertexAttribArray(g_AttribLocationVtxUV);
+    glEnableVertexAttribArray(g_AttribLocationVtxColor);
+    glVertexAttribPointer(g_AttribLocationVtxPos,   2, GL_FLOAT,         GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, pos));
+    glVertexAttribPointer(g_AttribLocationVtxUV,    2, GL_FLOAT,         GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, uv));
+    glVertexAttribPointer(g_AttribLocationVtxColor, 4, GL_UNSIGNED_BYTE, GL_TRUE,  sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, col));
+}
+
 // OpenGL3 Render function.
 // (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
 // Note that this implementation is little overcomplicated because we are saving/setting up/restoring every OpenGL state explicitly, in order to be able to run within any OpenGL engine that doesn't do so.
@@ -207,55 +258,14 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
         clip_origin_lower_left = false;
 #endif
 
-    // Setup render state: alpha-blending enabled, no face culling, no depth testing, scissor enabled, polygon fill
-    glEnable(GL_BLEND);
-    glBlendEquation(GL_FUNC_ADD);
-    glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
-    glDisable(GL_CULL_FACE);
-    glDisable(GL_DEPTH_TEST);
-    glEnable(GL_SCISSOR_TEST);
-#ifdef GL_POLYGON_MODE
-    glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
-#endif
-
-    // Setup viewport, orthographic projection matrix
-    // Our visible imgui space lies from draw_data->DisplayPos (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is (0,0) for single viewport apps.
-    glViewport(0, 0, (GLsizei)fb_width, (GLsizei)fb_height);
-    float L = draw_data->DisplayPos.x;
-    float R = draw_data->DisplayPos.x + draw_data->DisplaySize.x;
-    float T = draw_data->DisplayPos.y;
-    float B = draw_data->DisplayPos.y + draw_data->DisplaySize.y;
-    const float ortho_projection[4][4] =
-    {
-        { 2.0f/(R-L),   0.0f,         0.0f,   0.0f },
-        { 0.0f,         2.0f/(T-B),   0.0f,   0.0f },
-        { 0.0f,         0.0f,        -1.0f,   0.0f },
-        { (R+L)/(L-R),  (T+B)/(B-T),  0.0f,   1.0f },
-    };
-    glUseProgram(g_ShaderHandle);
-    glUniform1i(g_AttribLocationTex, 0);
-    glUniformMatrix4fv(g_AttribLocationProjMtx, 1, GL_FALSE, &ortho_projection[0][0]);
-#ifdef GL_SAMPLER_BINDING
-    glBindSampler(0, 0); // We use combined texture/sampler state. Applications using GL 3.3 may set that otherwise.
-#endif
-
+    // Setup desired GL state
     // Recreate the VAO every time (this is to easily allow multiple GL contexts to be rendered to. VAO are not shared among GL contexts)
     // The renderer would actually work without any VAO bound, but then our VertexAttrib calls would overwrite the default one currently bound.
-#ifndef IMGUI_IMPL_OPENGL_ES2
     GLuint vertex_array_object = 0;
+#ifndef IMGUI_IMPL_OPENGL_ES2
     glGenVertexArrays(1, &vertex_array_object);
-    glBindVertexArray(vertex_array_object);
 #endif
-
-    // Bind vertex/index buffers and setup attributes for ImDrawVert
-    glBindBuffer(GL_ARRAY_BUFFER, g_VboHandle);
-    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, g_ElementsHandle);
-    glEnableVertexAttribArray(g_AttribLocationVtxPos);
-    glEnableVertexAttribArray(g_AttribLocationVtxUV);
-    glEnableVertexAttribArray(g_AttribLocationVtxColor);
-    glVertexAttribPointer(g_AttribLocationVtxPos,   2, GL_FLOAT,         GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, pos));
-    glVertexAttribPointer(g_AttribLocationVtxUV,    2, GL_FLOAT,         GL_FALSE, sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, uv));
-    glVertexAttribPointer(g_AttribLocationVtxColor, 4, GL_UNSIGNED_BYTE, GL_TRUE,  sizeof(ImDrawVert), (GLvoid*)IM_OFFSETOF(ImDrawVert, col));
+    ImGui_ImplOpenGL3_SetupRenderState(draw_data, fb_width, fb_height, vertex_array_object);
 
     // Will project scissor/clipping rectangles into framebuffer space
     ImVec2 clip_off = draw_data->DisplayPos;         // (0,0) unless using multi-viewports
@@ -274,10 +284,14 @@ void    ImGui_ImplOpenGL3_RenderDrawData(ImDrawData* draw_data)
         for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
-            if (pcmd->UserCallback)
+            if (pcmd->UserCallback != NULL)
             {
-                // User callback (registered via ImDrawList::AddCallback)
-                pcmd->UserCallback(cmd_list, pcmd);
+                // User callback, registered via ImDrawList::AddCallback()
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    ImGui_ImplOpenGL3_SetupRenderState(draw_data, fb_width, fb_height, vertex_array_object);
+                else
+                    pcmd->UserCallback(cmd_list, pcmd);
             }
             else
             {

examples/imgui_impl_vulkan.cpp

@@ -21,8 +21,9 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
-//  2019-XX-XX: *BREAKING CHANGE*: Vulkan: Added ImageCount/MinImageCount fields in ImGui_ImplVulkan_InitInfo, required for initialization (was previously a hard #define IMGUI_VK_QUEUED_FRAMES 2). Added ImGui_ImplVulkan_SetMinImageCount().
-//  2019-XX-XX: Vulkan: Added VkInstance argument to ImGui_ImplVulkanH_CreateWindow() optional helper.
+//  2019-04-30: Vulkan: Added support for special ImDrawCallback_ResetRenderState callback to reset render state.
+//  2019-04-04: *BREAKING CHANGE*: Vulkan: Added ImageCount/MinImageCount fields in ImGui_ImplVulkan_InitInfo, required for initialization (was previously a hard #define IMGUI_VK_QUEUED_FRAMES 2). Added ImGui_ImplVulkan_SetMinImageCount().
+//  2019-04-04: Vulkan: Added VkInstance argument to ImGui_ImplVulkanH_CreateWindow() optional helper.
 //  2019-04-04: Vulkan: Avoid passing negative coordinates to vkCmdSetScissor, which debug validation layers do not like.
 //  2019-04-01: Vulkan: Support for 32-bit index buffer (#define ImDrawIdx unsigned int).
 //  2019-02-16: Vulkan: Viewport and clipping rectangles correctly using draw_data->FramebufferScale to allow retina display.
@@ -273,6 +274,49 @@ static void CreateOrResizeBuffer(VkBuffer& buffer, VkDeviceMemory& buffer_memory
     p_buffer_size = new_size;
 }
 
+static void ImGui_ImplVulkan_SetupRenderState(ImDrawData* draw_data, VkCommandBuffer command_buffer, ImGui_ImplVulkanH_FrameRenderBuffers* rb, int fb_width, int fb_height)
+{
+    // Bind pipeline and descriptor sets:
+    {
+        vkCmdBindPipeline(command_buffer, VK_PIPELINE_BIND_POINT_GRAPHICS, g_Pipeline);
+        VkDescriptorSet desc_set[1] = { g_DescriptorSet };
+        vkCmdBindDescriptorSets(command_buffer, VK_PIPELINE_BIND_POINT_GRAPHICS, g_PipelineLayout, 0, 1, desc_set, 0, NULL);
+    }
+
+    // Bind Vertex And Index Buffer:
+    {
+        VkBuffer vertex_buffers[1] = { rb->VertexBuffer };
+        VkDeviceSize vertex_offset[1] = { 0 };
+        vkCmdBindVertexBuffers(command_buffer, 0, 1, vertex_buffers, vertex_offset);
+        vkCmdBindIndexBuffer(command_buffer, rb->IndexBuffer, 0, sizeof(ImDrawIdx) == 2 ? VK_INDEX_TYPE_UINT16 : VK_INDEX_TYPE_UINT32);
+    }
+
+    // Setup viewport:
+    {
+        VkViewport viewport;
+        viewport.x = 0;
+        viewport.y = 0;
+        viewport.width = (float)fb_width;
+        viewport.height = (float)fb_height;
+        viewport.minDepth = 0.0f;
+        viewport.maxDepth = 1.0f;
+        vkCmdSetViewport(command_buffer, 0, 1, &viewport);
+    }
+
+    // Setup scale and translation:
+    // Our visible imgui space lies from draw_data->DisplayPps (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is (0,0) for single viewport apps.
+    {
+        float scale[2];
+        scale[0] = 2.0f / draw_data->DisplaySize.x;
+        scale[1] = 2.0f / draw_data->DisplaySize.y;
+        float translate[2];
+        translate[0] = -1.0f - draw_data->DisplayPos.x * scale[0];
+        translate[1] = -1.0f - draw_data->DisplayPos.y * scale[1];
+        vkCmdPushConstants(command_buffer, g_PipelineLayout, VK_SHADER_STAGE_VERTEX_BIT, sizeof(float) * 0, sizeof(float) * 2, scale);
+        vkCmdPushConstants(command_buffer, g_PipelineLayout, VK_SHADER_STAGE_VERTEX_BIT, sizeof(float) * 2, sizeof(float) * 2, translate);
+    }
+}
+
 // Render function
 // (this used to be set in io.RenderDrawListsFn and called by ImGui::Render(), but you can now call this directly from your main loop)
 void ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer command_buffer)
@@ -339,45 +383,8 @@ void ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer comm
         vkUnmapMemory(v->Device, rb->IndexBufferMemory);
     }
 
-    // Bind pipeline and descriptor sets:
-    {
-        vkCmdBindPipeline(command_buffer, VK_PIPELINE_BIND_POINT_GRAPHICS, g_Pipeline);
-        VkDescriptorSet desc_set[1] = { g_DescriptorSet };
-        vkCmdBindDescriptorSets(command_buffer, VK_PIPELINE_BIND_POINT_GRAPHICS, g_PipelineLayout, 0, 1, desc_set, 0, NULL);
-    }
-
-    // Bind Vertex And Index Buffer:
-    {
-        VkBuffer vertex_buffers[1] = { rb->VertexBuffer };
-        VkDeviceSize vertex_offset[1] = { 0 };
-        vkCmdBindVertexBuffers(command_buffer, 0, 1, vertex_buffers, vertex_offset);
-        vkCmdBindIndexBuffer(command_buffer, rb->IndexBuffer, 0, sizeof(ImDrawIdx) == 2 ? VK_INDEX_TYPE_UINT16 : VK_INDEX_TYPE_UINT32);
-    }
-
-    // Setup viewport:
-    {
-        VkViewport viewport;
-        viewport.x = 0;
-        viewport.y = 0;
-        viewport.width = (float)fb_width;
-        viewport.height = (float)fb_height;
-        viewport.minDepth = 0.0f;
-        viewport.maxDepth = 1.0f;
-        vkCmdSetViewport(command_buffer, 0, 1, &viewport);
-    }
-
-    // Setup scale and translation:
-    // Our visible imgui space lies from draw_data->DisplayPps (top left) to draw_data->DisplayPos+data_data->DisplaySize (bottom right). DisplayMin is (0,0) for single viewport apps.
-    {
-        float scale[2];
-        scale[0] = 2.0f / draw_data->DisplaySize.x;
-        scale[1] = 2.0f / draw_data->DisplaySize.y;
-        float translate[2];
-        translate[0] = -1.0f - draw_data->DisplayPos.x * scale[0];
-        translate[1] = -1.0f - draw_data->DisplayPos.y * scale[1];
-        vkCmdPushConstants(command_buffer, g_PipelineLayout, VK_SHADER_STAGE_VERTEX_BIT, sizeof(float) * 0, sizeof(float) * 2, scale);
-        vkCmdPushConstants(command_buffer, g_PipelineLayout, VK_SHADER_STAGE_VERTEX_BIT, sizeof(float) * 2, sizeof(float) * 2, translate);
-    }
+    // Setup desired Vulkan state
+    ImGui_ImplVulkan_SetupRenderState(draw_data, command_buffer, rb, fb_width, fb_height);
 
     // Will project scissor/clipping rectangles into framebuffer space
     ImVec2 clip_off = draw_data->DisplayPos;         // (0,0) unless using multi-viewports
@@ -392,10 +399,14 @@ void ImGui_ImplVulkan_RenderDrawData(ImDrawData* draw_data, VkCommandBuffer comm
         for (int cmd_i = 0; cmd_i < cmd_list->CmdBuffer.Size; cmd_i++)
         {
             const ImDrawCmd* pcmd = &cmd_list->CmdBuffer[cmd_i];
-            if (pcmd->UserCallback)
+            if (pcmd->UserCallback != NULL)
             {
-                // User callback (registered via ImDrawList::AddCallback)
-                pcmd->UserCallback(cmd_list, pcmd);
+                // User callback, registered via ImDrawList::AddCallback()
+                // (ImDrawCallback_ResetRenderState is a special callback value used by the user to request the renderer to reset render state.)
+                if (pcmd->UserCallback == ImDrawCallback_ResetRenderState)
+                    ImGui_ImplVulkan_SetupRenderState(draw_data, command_buffer, rb, fb_width, fb_height);
+                else
+                    pcmd->UserCallback(cmd_list, pcmd);
             }
             else
             {

imgui.cpp

@@ -381,6 +381,7 @@ CODE
  
 
  - 2019/04/29 (1.70) - fixed ImDrawList rectangles with thick lines (>1.0f) not being as thick as requested. If you have custom rendering using rectangles with thick lines, they will appear thicker now.
+ - 2019/04/29 (1.70) - removed GetContentRegionAvailWidth(), use GetContentRegionAvail().x instead. Kept inline redirection function (will obsolete).
  - 2019/03/04 (1.69) - renamed GetOverlayDrawList() to GetForegroundDrawList(). Kept redirection function (will obsolete).
  - 2019/02/26 (1.69) - renamed ImGuiColorEditFlags_RGB/ImGuiColorEditFlags_HSV/ImGuiColorEditFlags_HEX to ImGuiColorEditFlags_DisplayRGB/ImGuiColorEditFlags_DisplayHSV/ImGuiColorEditFlags_DisplayHex. Kept redirection enums (will obsolete).
  - 2019/02/14 (1.68) - made it illegal/assert when io.DisplayTime == 0.0f (with an exception for the first frame). If for some reason your time step calculation gives you a zero value, replace it with a dummy small value!
@@ -7064,11 +7065,6 @@ ImVec2 ImGui::GetContentRegionAvail()
     return GetContentRegionMaxScreen() - window->DC.CursorPos;
 }
 
-float ImGui::GetContentRegionAvailWidth()
-{
-    return GetContentRegionAvail().x;
-}
-
 // In window space (not screen space!)
 ImVec2 ImGui::GetWindowContentRegionMin()
 {
@@ -9435,16 +9431,16 @@ bool ImGui::BeginDragDropSource(ImGuiDragDropFlags flags)
                 return false;
             }
 
+            // Early out
+            if ((window->DC.LastItemStatusFlags & ImGuiItemStatusFlags_HoveredRect) == 0 && (g.ActiveId == 0 || g.ActiveIdWindow != window))
+                return false;
+
             // Magic fallback (=somehow reprehensible) to handle items with no assigned ID, e.g. Text(), Image()
             // We build a throwaway ID based on current ID stack + relative AABB of items in window.
             // THE IDENTIFIER WON'T SURVIVE ANY REPOSITIONING OF THE WIDGET, so if your widget moves your dragging operation will be canceled.
             // We don't need to maintain/call ClearActiveID() as releasing the button will early out this function and trigger !ActiveIdIsAlive.
-            bool is_hovered = (window->DC.LastItemStatusFlags & ImGuiItemStatusFlags_HoveredRect) != 0;
-            if (!is_hovered && (g.ActiveId == 0 || g.ActiveIdWindow != window))
-                return false;
             source_id = window->DC.LastItemId = window->GetIDFromRectangle(window->DC.LastItemRect);
-            if (is_hovered)
-                SetHoveredID(source_id);
+            bool is_hovered = ItemHoverable(window->DC.LastItemRect, source_id);
             if (is_hovered && g.IO.MouseClicked[mouse_button])
             {
                 SetActiveID(source_id, window);
@@ -10051,14 +10047,15 @@ static void* SettingsHandlerWindow_ReadOpen(ImGuiContext*, ImGuiSettingsHandler*
     return (void*)settings;
 }
 
-static void SettingsHandlerWindow_ReadLine(ImGuiContext*, ImGuiSettingsHandler*, void* entry, const char* line)
+static void SettingsHandlerWindow_ReadLine(ImGuiContext* ctx, ImGuiSettingsHandler*, void* entry, const char* line)
 {
+    ImGuiContext& g = *ctx;
     ImGuiWindowSettings* settings = (ImGuiWindowSettings*)entry;
     float x, y;
     int i;
     ImU32 u1;
     if (sscanf(line, "Pos=%f,%f", &x, &y) == 2)                 { settings->Pos = ImVec2(x, y); }
-    else if (sscanf(line, "Size=%f,%f", &x, &y) == 2)           { settings->Size = ImMax(ImVec2(x, y), GImGui->Style.WindowMinSize); }
+    else if (sscanf(line, "Size=%f,%f", &x, &y) == 2)           { settings->Size = ImMax(ImVec2(x, y), g.Style.WindowMinSize); }
     else if (sscanf(line, "ViewportId=0x%08X", &u1) == 1)       { settings->ViewportId = u1; }
     else if (sscanf(line, "ViewportPos=%f,%f", &x, &y) == 2)    { settings->ViewportPos = ImVec2(x, y); }
     else if (sscanf(line, "Collapsed=%d", &i) == 1)             { settings->Collapsed = (i != 0); }

imgui.h

@@ -300,7 +300,6 @@ namespace ImGui
     // - Those functions are bound to be redesigned soon (they are confusing, incomplete and return values in local window coordinates which increases confusion)
     IMGUI_API ImVec2        GetContentRegionMax();                                          // current content boundaries (typically window boundaries including scrolling, or current column boundaries), in windows coordinates
     IMGUI_API ImVec2        GetContentRegionAvail();                                        // == GetContentRegionMax() - GetCursorPos()
-    IMGUI_API float         GetContentRegionAvailWidth();                                   // == GetContentRegionAvail().x
     IMGUI_API ImVec2        GetWindowContentRegionMin();                                    // content boundaries min (roughly (0,0)-Scroll), in window coordinates
     IMGUI_API ImVec2        GetWindowContentRegionMax();                                    // content boundaries max (roughly (0,0)+Size-Scroll) where Size can be override with SetNextWindowContentSize(), in window coordinates
     IMGUI_API float         GetWindowContentRegionWidth();                                  //
@@ -1621,6 +1620,8 @@ struct ImGuiWindowClass
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
 namespace ImGui
 {
+    // OBSOLETED in 1.70 (from May 2019)
+    static inline float GetContentRegionAvailWidth()          { return GetContentRegionAvail().x; }
     // OBSOLETED in 1.69 (from Mar 2019)
     static inline ImDrawList* GetOverlayDrawList()            { return GetForegroundDrawList(); }
     // OBSOLETED in 1.66 (from Sep 2018)
@@ -1850,11 +1851,18 @@ struct ImColor
 
 // Draw callbacks for advanced uses.
 // NB: You most likely do NOT need to use draw callbacks just to create your own widget or customized UI rendering,
-// you can poke into the draw list for that! Draw callback may be useful for example to: A) Change your GPU render state,
-// B) render a complex 3D scene inside a UI element without an intermediate texture/render target, etc.
+// you can poke into the draw list for that! Draw callback may be useful for example to: 
+//  A) Change your GPU render state,
+//  B) render a complex 3D scene inside a UI element without an intermediate texture/render target, etc.
 // The expected behavior from your rendering function is 'if (cmd.UserCallback != NULL) { cmd.UserCallback(parent_list, cmd); } else { RenderTriangles() }'
 typedef void (*ImDrawCallback)(const ImDrawList* parent_list, const ImDrawCmd* cmd);
 
+// Special Draw Callback value to request renderer back-end to reset the graphics/render state.
+// The renderer back-end needs to handle this special value, otherwise it will crash trying to call a function at this address.
+// This is useful for example if you submitted callbacks which you know have altered the render state and you want it to be restored.
+// It is not done by default because they are many perfectly useful way of altering render state for imgui contents (e.g. changing shader/blending settings before an Image call).
+#define ImDrawCallback_ResetRenderState     (ImDrawCallback)(-1)
+
 // Typically, 1 command = 1 GPU draw call (unless command is a callback)
 struct ImDrawCmd
 {

imgui_demo.cpp

@@ -1810,9 +1810,9 @@ static void ShowDemoWindowLayout()
         ImGui::SetNextItemWidth(ImGui::GetWindowWidth() * 0.5f);
         ImGui::DragFloat("float##2", &f);
 
-        ImGui::Text("SetNextItemWidth/PushItemWidth(GetContentRegionAvailWidth() * 0.5f)");
+        ImGui::Text("SetNextItemWidth/PushItemWidth(GetContentRegionAvail().x * 0.5f)");
         ImGui::SameLine(); HelpMarker("Half of available width.\n(~ right-cursor_pos)\n(works within a column set)");
-        ImGui::SetNextItemWidth(ImGui::GetContentRegionAvailWidth() * 0.5f);
+        ImGui::SetNextItemWidth(ImGui::GetContentRegionAvail().x * 0.5f);
         ImGui::DragFloat("float##3", &f);
 
         ImGui::Text("SetNextItemWidth/PushItemWidth(-100)");