Backends: DX10, DX11, DX12: honor FramebufferScale. (#8412)

# Conflicts:
#	backends/imgui_impl_dx11.cpp
#	backends/imgui_impl_dx12.cpp

backends/imgui_impl_dx10.cpp

@@ -15,6 +15,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-05-07: DirectX10: Honor draw_data->FramebufferScale to allow for custom backends and experiment using it (consistently with other renderer backends, even though in normal condition it is not set under Windows).
 //  2025-01-06: DirectX10: Expose selected render state in ImGui_ImplDX10_RenderState, which you can access in 'void* platform_io.Renderer_RenderState' during draw callbacks.
 //  2024-10-07: DirectX10: Changed default texture sampler to Clamp instead of Repeat/Wrap.
 //  2022-10-11: Using 'nullptr' instead of 'NULL' as per our switch to C++11.
@@ -88,8 +89,8 @@ static void ImGui_ImplDX10_SetupRenderState(ImDrawData* draw_data, ID3D10Device*
 
     // Setup viewport
     D3D10_VIEWPORT vp = {};
-    vp.Width = (UINT)draw_data->DisplaySize.x;
-    vp.Height = (UINT)draw_data->DisplaySize.y;
+    vp.Width = (UINT)(draw_data->DisplaySize.x * draw_data->FramebufferScale.x);
+    vp.Height = (UINT)(draw_data->DisplaySize.y * draw_data->FramebufferScale.y);
     vp.MinDepth = 0.0f;
     vp.MaxDepth = 1.0f;
     vp.TopLeftX = vp.TopLeftY = 0;
@@ -246,6 +247,7 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
     int global_vtx_offset = 0;
     int global_idx_offset = 0;
     ImVec2 clip_off = draw_data->DisplayPos;
+    ImVec2 clip_scale = draw_data->FramebufferScale;
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
         const ImDrawList* draw_list = draw_data->CmdLists[n];
@@ -264,8 +266,8 @@ void ImGui_ImplDX10_RenderDrawData(ImDrawData* draw_data)
             else
             {
                 // Project scissor/clipping rectangles into framebuffer space
-                ImVec2 clip_min(pcmd->ClipRect.x - clip_off.x, pcmd->ClipRect.y - clip_off.y);
-                ImVec2 clip_max(pcmd->ClipRect.z - clip_off.x, pcmd->ClipRect.w - clip_off.y);
+                ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
+                ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y);
                 if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y)
                     continue;
 

backends/imgui_impl_dx11.cpp

@@ -16,6 +16,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-05-07: DirectX11: Honor draw_data->FramebufferScale to allow for custom backends and experiment using it (consistently with other renderer backends, even though in normal condition it is not set under Windows).
 //  2025-01-06: DirectX11: Expose VertexConstantBuffer in ImGui_ImplDX11_RenderState. Reset projection matrix in ImDrawCallback_ResetRenderState handler.
 //  2024-10-07: DirectX11: Changed default texture sampler to Clamp instead of Repeat/Wrap.
 //  2024-10-07: DirectX11: Expose selected render state in ImGui_ImplDX11_RenderState, which you can access in 'void* platform_io.Renderer_RenderState' during draw callbacks.
@@ -91,8 +92,8 @@ static void ImGui_ImplDX11_SetupRenderState(ImDrawData* draw_data, ID3D11DeviceC
 
     // Setup viewport
     D3D11_VIEWPORT vp = {};
-    vp.Width = draw_data->DisplaySize.x;
-    vp.Height = draw_data->DisplaySize.y;
+    vp.Width = draw_data->DisplaySize.x * draw_data->FramebufferScale.x;
+    vp.Height = draw_data->DisplaySize.y * draw_data->FramebufferScale.y;
     vp.MinDepth = 0.0f;
     vp.MaxDepth = 1.0f;
     vp.TopLeftX = vp.TopLeftY = 0;
@@ -260,6 +261,7 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
     int global_idx_offset = 0;
     int global_vtx_offset = 0;
     ImVec2 clip_off = draw_data->DisplayPos;
+    ImVec2 clip_scale = draw_data->FramebufferScale;
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
         const ImDrawList* draw_list = draw_data->CmdLists[n];
@@ -278,8 +280,8 @@ void ImGui_ImplDX11_RenderDrawData(ImDrawData* draw_data)
             else
             {
                 // Project scissor/clipping rectangles into framebuffer space
-                ImVec2 clip_min(pcmd->ClipRect.x - clip_off.x, pcmd->ClipRect.y - clip_off.y);
-                ImVec2 clip_max(pcmd->ClipRect.z - clip_off.x, pcmd->ClipRect.w - clip_off.y);
+                ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
+                ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y);
                 if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y)
                     continue;
 

backends/imgui_impl_dx12.cpp

@@ -19,6 +19,7 @@
 
 // CHANGELOG
 // (minor and older changes stripped away, please see git history for details)
+//  2025-05-07: DirectX12: Honor draw_data->FramebufferScale to allow for custom backends and experiment using it (consistently with other renderer backends, even though in normal condition it is not set under Windows).
 //  2025-02-24: DirectX12: Fixed an issue where ImGui_ImplDX12_Init() signature change from 2024-11-15 combined with change from 2025-01-15 made legacy ImGui_ImplDX12_Init() crash. (#8429)
 //  2025-01-15: DirectX12: Texture upload use the command queue provided in ImGui_ImplDX12_InitInfo instead of creating its own.
 //  2024-12-09: DirectX12: Let user specifies the DepthStencilView format by setting ImGui_ImplDX12_InitInfo::DSVFormat.
@@ -138,8 +139,8 @@ static void ImGui_ImplDX12_SetupRenderState(ImDrawData* draw_data, ID3D12Graphic
 
     // Setup viewport
     D3D12_VIEWPORT vp = {};
-    vp.Width = draw_data->DisplaySize.x;
-    vp.Height = draw_data->DisplaySize.y;
+    vp.Width = draw_data->DisplaySize.x * draw_data->FramebufferScale.x;
+    vp.Height = draw_data->DisplaySize.y * draw_data->FramebufferScale.y;
     vp.MinDepth = 0.0f;
     vp.MaxDepth = 1.0f;
     vp.TopLeftX = vp.TopLeftY = 0.0f;
@@ -274,6 +275,7 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
     int global_vtx_offset = 0;
     int global_idx_offset = 0;
     ImVec2 clip_off = draw_data->DisplayPos;
+    ImVec2 clip_scale = draw_data->FramebufferScale;
     for (int n = 0; n < draw_data->CmdListsCount; n++)
     {
         const ImDrawList* draw_list = draw_data->CmdLists[n];
@@ -292,8 +294,8 @@ void ImGui_ImplDX12_RenderDrawData(ImDrawData* draw_data, ID3D12GraphicsCommandL
             else
             {
                 // Project scissor/clipping rectangles into framebuffer space
-                ImVec2 clip_min(pcmd->ClipRect.x - clip_off.x, pcmd->ClipRect.y - clip_off.y);
-                ImVec2 clip_max(pcmd->ClipRect.z - clip_off.x, pcmd->ClipRect.w - clip_off.y);
+                ImVec2 clip_min((pcmd->ClipRect.x - clip_off.x) * clip_scale.x, (pcmd->ClipRect.y - clip_off.y) * clip_scale.y);
+                ImVec2 clip_max((pcmd->ClipRect.z - clip_off.x) * clip_scale.x, (pcmd->ClipRect.w - clip_off.y) * clip_scale.y);
                 if (clip_max.x <= clip_min.x || clip_max.y <= clip_min.y)
                     continue;
 

docs/CHANGELOG.txt

@@ -116,6 +116,9 @@ Other changes:
 - Backends: SDLGPU3: Made ImGui_ImplSDLGPU3_PrepareDrawData() reuse GPU Transfer Buffers which
   were unusually slow to recreate every frame. Much faster now. (#8534) [@ocornut, @TheMode]
 - Backends: SDLGPU3: added support for ImDrawCallback_ResetRenderState. (#8599)
+- Backends: DirectX10, DirectX11, DirectX12: Honor FramebufferScale to allow for custom
+  platform backends and experiments using it (consistently with other renderer backends,
+  even though in normal condition it is not set under Windows). (#8412) [@WSSDude]
 - Backends: Vulkan: Deep-copy ImGui_ImplVulkan_InitInfo::PipelineRenderingCreateInfo's
   pColorAttachmentFormats buffer when set, in order to reduce common user-error of
   specifying a pointer to data that gets out of scope. (#8282)