ImFontAtlas: Moved mouse cursor data out of ImGuiContext, fix drawing them with multiple context. Also remove the last remaining undesirable dependency on GImGui in imgui_draw.cpp, finishing the work recently done with ImDrawListSharedData. Hurra! (#939)

imgui.cpp

@@ -3069,17 +3069,16 @@ void ImGui::Render()
         g.DrawDataBuilder.FlattenIntoSingleLayer();
 
         // Draw software mouse cursor if requested
-        if (g.IO.MouseDrawCursor)
+        ImVec2 offset, size, uv[4];
+        if (g.IO.MouseDrawCursor && g.IO.Fonts->GetMouseCursorTexData(g.MouseCursor, &offset, &size, &uv[0], &uv[2]))
         {
-            const ImGuiMouseCursorData& cursor_data = g.MouseCursorData[g.MouseCursor];
-            const ImVec2 pos = g.IO.MousePos - cursor_data.HotOffset;
-            const ImVec2 size = cursor_data.Size;
+            const ImVec2 pos = g.IO.MousePos - offset;
             const ImTextureID tex_id = g.IO.Fonts->TexID;
             g.OverlayDrawList.PushTextureID(tex_id);
-            g.OverlayDrawList.AddImage(tex_id, pos+ImVec2(1,0), pos+ImVec2(1,0) + size, cursor_data.TexUvMin[1], cursor_data.TexUvMax[1], IM_COL32(0,0,0,48));        // Shadow
-            g.OverlayDrawList.AddImage(tex_id, pos+ImVec2(2,0), pos+ImVec2(2,0) + size, cursor_data.TexUvMin[1], cursor_data.TexUvMax[1], IM_COL32(0,0,0,48));        // Shadow
-            g.OverlayDrawList.AddImage(tex_id, pos,             pos + size,             cursor_data.TexUvMin[1], cursor_data.TexUvMax[1], IM_COL32(0,0,0,255));       // Black border
-            g.OverlayDrawList.AddImage(tex_id, pos,             pos + size,             cursor_data.TexUvMin[0], cursor_data.TexUvMax[0], IM_COL32(255,255,255,255)); // White fill
+            g.OverlayDrawList.AddImage(tex_id, pos+ImVec2(1,0), pos+ImVec2(1,0) + size, uv[2], uv[3], IM_COL32(0,0,0,48));        // Shadow
+            g.OverlayDrawList.AddImage(tex_id, pos+ImVec2(2,0), pos+ImVec2(2,0) + size, uv[2], uv[3], IM_COL32(0,0,0,48));        // Shadow
+            g.OverlayDrawList.AddImage(tex_id, pos,             pos + size,             uv[2], uv[3], IM_COL32(0,0,0,255));       // Black border
+            g.OverlayDrawList.AddImage(tex_id, pos,             pos + size,             uv[0], uv[1], IM_COL32(255,255,255,255)); // White fill
             g.OverlayDrawList.PopTextureID();
         }
         if (!g.OverlayDrawList.VtxBuffer.empty())

imgui.h

@@ -1611,9 +1611,12 @@ struct ImFontAtlas
 
     IMGUI_API int       AddCustomRectRegular(unsigned int id, int width, int height);                                                                   // Id needs to be >= 0x10000. Id >= 0x80000000 are reserved for ImGui and ImDrawList
     IMGUI_API int       AddCustomRectFontGlyph(ImFont* font, ImWchar id, int width, int height, float advance_x, const ImVec2& offset = ImVec2(0,0));   // Id needs to be < 0x10000 to register a rectangle to map into a specific font.
-    IMGUI_API void      CalcCustomRectUV(const CustomRect* rect, ImVec2* out_uv_min, ImVec2* out_uv_max);
     const CustomRect*   GetCustomRectByIndex(int index) const { if (index < 0) return NULL; return &CustomRects[index]; }
 
+    // Internals
+    IMGUI_API void      CalcCustomRectUV(const CustomRect* rect, ImVec2* out_uv_min, ImVec2* out_uv_max);
+    IMGUI_API bool      GetMouseCursorTexData(ImGuiMouseCursor cursor, ImVec2* out_offset, ImVec2* out_size, ImVec2 out_uv_border[2], ImVec2 out_uv_fill[2]);
+
     //-------------------------------------------
     // Members
     //-------------------------------------------

imgui_draw.cpp

@@ -1352,7 +1352,6 @@ static const ImVec2 FONT_ATLAS_DEFAULT_TEX_CURSOR_DATA[ImGuiMouseCursor_Count_][
     { ImVec2(55,0), ImVec2(17,17), ImVec2( 9, 9) }, // ImGuiMouseCursor_ResizeNWSE
 };
 
-
 ImFontAtlas::ImFontAtlas()
 {
     TexID = NULL;
@@ -1609,6 +1608,26 @@ void ImFontAtlas::CalcCustomRectUV(const CustomRect* rect, ImVec2* out_uv_min, I
     *out_uv_max = ImVec2((float)(rect->X + rect->Width) / TexWidth, (float)(rect->Y + rect->Height) / TexHeight);
 }
 
+bool ImFontAtlas::GetMouseCursorTexData(ImGuiMouseCursor cursor_type, ImVec2* out_offset, ImVec2* out_size, ImVec2 out_uv_border[2], ImVec2 out_uv_fill[2])
+{
+    if (cursor_type <= ImGuiMouseCursor_None || cursor_type >= ImGuiMouseCursor_Count_)
+        return false;
+
+    ImFontAtlas::CustomRect& r = CustomRects[CustomRectIds[0]];
+    IM_ASSERT(r.ID == FONT_ATLAS_DEFAULT_TEX_DATA_ID);
+    ImVec2 uv_scale(1.0f / TexWidth, 1.0f / TexHeight);
+    ImVec2 pos = FONT_ATLAS_DEFAULT_TEX_CURSOR_DATA[cursor_type][0] + ImVec2((float)r.X, (float)r.Y);
+    ImVec2 size = FONT_ATLAS_DEFAULT_TEX_CURSOR_DATA[cursor_type][1];
+    *out_size = size;
+    *out_offset = FONT_ATLAS_DEFAULT_TEX_CURSOR_DATA[cursor_type][2];
+    out_uv_border[0] = (pos) * uv_scale;
+    out_uv_border[1] = (pos + size) * uv_scale;
+    pos.x += FONT_ATLAS_DEFAULT_TEX_DATA_W_HALF + 1;
+    out_uv_fill[0] = (pos) * uv_scale;
+    out_uv_fill[1] = (pos + size) * uv_scale;
+    return true;
+}
+
 bool    ImFontAtlas::Build()
 {
     return ImFontAtlasBuildWithStbTruetype(this);
@@ -1891,22 +1910,6 @@ static void ImFontAtlasBuildRenderDefaultTexData(ImFontAtlas* atlas)
         }
     const ImVec2 tex_uv_scale(1.0f / atlas->TexWidth, 1.0f / atlas->TexHeight);
     atlas->TexUvWhitePixel = ImVec2((r.X + 0.5f) * tex_uv_scale.x, (r.Y + 0.5f) * tex_uv_scale.y);
-
-    // Setup mouse cursors
-    for (int type = 0; type < ImGuiMouseCursor_Count_; type++)
-    {
-        ImGuiMouseCursorData& cursor_data = GImGui->MouseCursorData[type];
-        ImVec2 pos = FONT_ATLAS_DEFAULT_TEX_CURSOR_DATA[type][0] + ImVec2((float)r.X, (float)r.Y);
-        const ImVec2 size = FONT_ATLAS_DEFAULT_TEX_CURSOR_DATA[type][1];
-        cursor_data.Type = type;
-        cursor_data.Size = size;
-        cursor_data.HotOffset = FONT_ATLAS_DEFAULT_TEX_CURSOR_DATA[type][2];
-        cursor_data.TexUvMin[0] = (pos) * tex_uv_scale;
-        cursor_data.TexUvMax[0] = (pos + size) * tex_uv_scale;
-        pos.x += FONT_ATLAS_DEFAULT_TEX_DATA_W_HALF + 1;
-        cursor_data.TexUvMin[1] = (pos) * tex_uv_scale;
-        cursor_data.TexUvMax[1] = (pos + size) * tex_uv_scale;
-    }
 }
 
 void ImFontAtlasBuildFinish(ImFontAtlas* atlas)

imgui_internal.h

@@ -38,7 +38,6 @@ struct ImGuiGroupData;
 struct ImGuiMenuColumns;
 struct ImGuiDrawContext;
 struct ImGuiTextEditState;
-struct ImGuiMouseCursorData;
 struct ImGuiPopupRef;
 struct ImGuiWindow;
 struct ImGuiWindowSettings;
@@ -382,16 +381,6 @@ struct ImGuiSettingsHandler
     ImGuiSettingsHandler() { memset(this, 0, sizeof(*this)); }
 };
 
-// Mouse cursor data (used when io.MouseDrawCursor is set)
-struct ImGuiMouseCursorData
-{
-    ImGuiMouseCursor    Type;
-    ImVec2              HotOffset;
-    ImVec2              Size;
-    ImVec2              TexUvMin[2];
-    ImVec2              TexUvMax[2];
-};
-
 // Storage for current popup stack
 struct ImGuiPopupRef
 {
@@ -557,7 +546,6 @@ struct ImGuiContext
     float                   ModalWindowDarkeningRatio;
     ImDrawList              OverlayDrawList;                    // Optional software render of mouse cursors, if io.MouseDrawCursor is set + a few debug overlays
     ImGuiMouseCursor        MouseCursor;
-    ImGuiMouseCursorData    MouseCursorData[ImGuiMouseCursor_Count_];
 
     // Drag and Drop
     bool                    DragDropActive;
@@ -645,7 +633,6 @@ struct ImGuiContext
         OverlayDrawList._Data = &DrawListSharedData;
         OverlayDrawList._OwnerName = "##Overlay"; // Give it a name for debugging
         MouseCursor = ImGuiMouseCursor_Arrow;
-        memset(MouseCursorData, 0, sizeof(MouseCursorData));
 
         DragDropActive = false;
         DragDropSourceFlags = 0;