Internal: Refactor: Moved RenderColorRectWithAlphaCheckerboard() to imgui_draw.cpp, tweaked signature.

Author: ocornut

imgui.cpp

@@ -1791,10 +1791,19 @@ int ImTextCountUtf8BytesFromStr(const ImWchar* in_text, const ImWchar* in_text_e
 }
 
 //-----------------------------------------------------------------------------
-// [SECTION] MISC HELPERS/UTILTIES (Color functions)
+// [SECTION] MISC HELPERS/UTILITIES (Color functions)
 // Note: The Convert functions are early design which are not consistent with other API.
 //-----------------------------------------------------------------------------
 
+IMGUI_API ImU32 ImAlphaBlendColors(ImU32 col_a, ImU32 col_b)
+{
+    float t = ((col_b >> IM_COL32_A_SHIFT) & 0xFF) / 255.f;
+    int r = ImLerp((int)(col_a >> IM_COL32_R_SHIFT) & 0xFF, (int)(col_b >> IM_COL32_R_SHIFT) & 0xFF, t);
+    int g = ImLerp((int)(col_a >> IM_COL32_G_SHIFT) & 0xFF, (int)(col_b >> IM_COL32_G_SHIFT) & 0xFF, t);
+    int b = ImLerp((int)(col_a >> IM_COL32_B_SHIFT) & 0xFF, (int)(col_b >> IM_COL32_B_SHIFT) & 0xFF, t);
+    return IM_COL32(r, g, b, 0xFF);
+}
+
 ImVec4 ImGui::ColorConvertU32ToFloat4(ImU32 in)
 {
     float s = 1.0f/255.0f;

imgui_draw.cpp

@@ -3172,6 +3172,7 @@ void ImFont::RenderText(ImDrawList* draw_list, float size, ImVec2 pos, ImU32 col
 // - RenderRectFilledRangeH()
 //-----------------------------------------------------------------------------
 // Function in need of a redesign (legacy mess)
+// - RenderColorRectWithAlphaCheckerboard()
 //-----------------------------------------------------------------------------
 
 // Render an arrow aimed to be aligned with text (p_min is a position in the same space text would be positioned). To e.g. denote expanded/collapsed state
@@ -3329,6 +3330,43 @@ void ImGui::RenderRectFilledRangeH(ImDrawList* draw_list, const ImRect& rect, Im
     draw_list->PathFillConvex(col);
 }
 
+// Helper for ColorPicker4()
+// NB: This is rather brittle and will show artifact when rounding this enabled if rounded corners overlap multiple cells. Caller currently responsible for avoiding that.
+// Spent a non reasonable amount of time trying to getting this right for ColorButton with rounding+anti-aliasing+ImGuiColorEditFlags_HalfAlphaPreview flag + various grid sizes and offsets, and eventually gave up... probably more reasonable to disable rounding alltogether.
+// FIXME: uses ImGui::GetColorU32
+void ImGui::RenderColorRectWithAlphaCheckerboard(ImDrawList* draw_list, ImVec2 p_min, ImVec2 p_max, ImU32 col, float grid_step, ImVec2 grid_off, float rounding, int rounding_corners_flags)
+{
+    if (((col & IM_COL32_A_MASK) >> IM_COL32_A_SHIFT) < 0xFF)
+    {
+        ImU32 col_bg1 = ImGui::GetColorU32(ImAlphaBlendColors(IM_COL32(204, 204, 204, 255), col));
+        ImU32 col_bg2 = ImGui::GetColorU32(ImAlphaBlendColors(IM_COL32(128, 128, 128, 255), col));
+        draw_list->AddRectFilled(p_min, p_max, col_bg1, rounding, rounding_corners_flags);
+
+        int yi = 0;
+        for (float y = p_min.y + grid_off.y; y < p_max.y; y += grid_step, yi++)
+        {
+            float y1 = ImClamp(y, p_min.y, p_max.y), y2 = ImMin(y + grid_step, p_max.y);
+            if (y2 <= y1)
+                continue;
+            for (float x = p_min.x + grid_off.x + (yi & 1) * grid_step; x < p_max.x; x += grid_step * 2.0f)
+            {
+                float x1 = ImClamp(x, p_min.x, p_max.x), x2 = ImMin(x + grid_step, p_max.x);
+                if (x2 <= x1)
+                    continue;
+                int rounding_corners_flags_cell = 0;
+                if (y1 <= p_min.y) { if (x1 <= p_min.x) rounding_corners_flags_cell |= ImDrawCornerFlags_TopLeft; if (x2 >= p_max.x) rounding_corners_flags_cell |= ImDrawCornerFlags_TopRight; }
+                if (y2 >= p_max.y) { if (x1 <= p_min.x) rounding_corners_flags_cell |= ImDrawCornerFlags_BotLeft; if (x2 >= p_max.x) rounding_corners_flags_cell |= ImDrawCornerFlags_BotRight; }
+                rounding_corners_flags_cell &= rounding_corners_flags;
+                draw_list->AddRectFilled(ImVec2(x1, y1), ImVec2(x2, y2), col_bg2, rounding_corners_flags_cell ? rounding : 0.0f, rounding_corners_flags_cell);
+            }
+        }
+    }
+    else
+    {
+        draw_list->AddRectFilled(p_min, p_max, col, rounding, rounding_corners_flags);
+    }
+}
+
 //-----------------------------------------------------------------------------
 // [SECTION] Decompression code
 //-----------------------------------------------------------------------------

imgui_internal.h

@@ -218,6 +218,9 @@ IMGUI_API ImU32         ImHashStr(const char* data, size_t data_size = 0, ImU32
 static inline ImU32     ImHash(const void* data, int size, ImU32 seed = 0) { return size ? ImHashData(data, (size_t)size, seed) : ImHashStr((const char*)data, 0, seed); } // [moved to ImHashStr/ImHashData in 1.68]
 #endif
 
+// Helpers: Color Blending
+IMGUI_API ImU32         ImAlphaBlendColors(ImU32 col_a, ImU32 col_b);
+
 // Helpers: Bit manipulation
 static inline bool      ImIsPowerOfTwo(int v)           { return v != 0 && (v & (v - 1)) == 0; }
 static inline int       ImUpperPowerOfTwo(int v)        { v--; v |= v >> 1; v |= v >> 2; v |= v >> 4; v |= v >> 8; v |= v >> 16; v++; return v; }
@@ -1812,7 +1815,7 @@ namespace ImGui
     IMGUI_API void          RenderTextEllipsis(ImDrawList* draw_list, const ImVec2& pos_min, const ImVec2& pos_max, float clip_max_x, float ellipsis_max_x, const char* text, const char* text_end, const ImVec2* text_size_if_known);
     IMGUI_API void          RenderFrame(ImVec2 p_min, ImVec2 p_max, ImU32 fill_col, bool border = true, float rounding = 0.0f);
     IMGUI_API void          RenderFrameBorder(ImVec2 p_min, ImVec2 p_max, float rounding = 0.0f);
-    IMGUI_API void          RenderColorRectWithAlphaCheckerboard(ImVec2 p_min, ImVec2 p_max, ImU32 fill_col, float grid_step, ImVec2 grid_off, float rounding = 0.0f, int rounding_corners_flags = ~0);
+    IMGUI_API void          RenderColorRectWithAlphaCheckerboard(ImDrawList* draw_list, ImVec2 p_min, ImVec2 p_max, ImU32 fill_col, float grid_step, ImVec2 grid_off, float rounding = 0.0f, int rounding_corners_flags = ~0);
     IMGUI_API void          RenderNavHighlight(const ImRect& bb, ImGuiID id, ImGuiNavHighlightFlags flags = ImGuiNavHighlightFlags_TypeDefault); // Navigation highlight
     IMGUI_API const char*   FindRenderedTextEnd(const char* text, const char* text_end = NULL); // Find the optional ## from which we stop displaying text.
     IMGUI_API void          LogRenderedText(const ImVec2* ref_pos, const char* text, const char* text_end = NULL);

imgui_widgets.cpp

@@ -4493,52 +4493,6 @@ bool ImGui::ColorPicker3(const char* label, float col[3], ImGuiColorEditFlags fl
     return true;
 }
 
-static inline ImU32 ImAlphaBlendColor(ImU32 col_a, ImU32 col_b)
-{
-    float t = ((col_b >> IM_COL32_A_SHIFT) & 0xFF) / 255.f;
-    int r = ImLerp((int)(col_a >> IM_COL32_R_SHIFT) & 0xFF, (int)(col_b >> IM_COL32_R_SHIFT) & 0xFF, t);
-    int g = ImLerp((int)(col_a >> IM_COL32_G_SHIFT) & 0xFF, (int)(col_b >> IM_COL32_G_SHIFT) & 0xFF, t);
-    int b = ImLerp((int)(col_a >> IM_COL32_B_SHIFT) & 0xFF, (int)(col_b >> IM_COL32_B_SHIFT) & 0xFF, t);
-    return IM_COL32(r, g, b, 0xFF);
-}
-
-// Helper for ColorPicker4()
-// NB: This is rather brittle and will show artifact when rounding this enabled if rounded corners overlap multiple cells. Caller currently responsible for avoiding that.
-// I spent a non reasonable amount of time trying to getting this right for ColorButton with rounding+anti-aliasing+ImGuiColorEditFlags_HalfAlphaPreview flag + various grid sizes and offsets, and eventually gave up... probably more reasonable to disable rounding alltogether.
-void ImGui::RenderColorRectWithAlphaCheckerboard(ImVec2 p_min, ImVec2 p_max, ImU32 col, float grid_step, ImVec2 grid_off, float rounding, int rounding_corners_flags)
-{
-    ImGuiWindow* window = GetCurrentWindow();
-    if (((col & IM_COL32_A_MASK) >> IM_COL32_A_SHIFT) < 0xFF)
-    {
-        ImU32 col_bg1 = GetColorU32(ImAlphaBlendColor(IM_COL32(204,204,204,255), col));
-        ImU32 col_bg2 = GetColorU32(ImAlphaBlendColor(IM_COL32(128,128,128,255), col));
-        window->DrawList->AddRectFilled(p_min, p_max, col_bg1, rounding, rounding_corners_flags);
-
-        int yi = 0;
-        for (float y = p_min.y + grid_off.y; y < p_max.y; y += grid_step, yi++)
-        {
-            float y1 = ImClamp(y, p_min.y, p_max.y), y2 = ImMin(y + grid_step, p_max.y);
-            if (y2 <= y1)
-                continue;
-            for (float x = p_min.x + grid_off.x + (yi & 1) * grid_step; x < p_max.x; x += grid_step * 2.0f)
-            {
-                float x1 = ImClamp(x, p_min.x, p_max.x), x2 = ImMin(x + grid_step, p_max.x);
-                if (x2 <= x1)
-                    continue;
-                int rounding_corners_flags_cell = 0;
-                if (y1 <= p_min.y) { if (x1 <= p_min.x) rounding_corners_flags_cell |= ImDrawCornerFlags_TopLeft; if (x2 >= p_max.x) rounding_corners_flags_cell |= ImDrawCornerFlags_TopRight; }
-                if (y2 >= p_max.y) { if (x1 <= p_min.x) rounding_corners_flags_cell |= ImDrawCornerFlags_BotLeft; if (x2 >= p_max.x) rounding_corners_flags_cell |= ImDrawCornerFlags_BotRight; }
-                rounding_corners_flags_cell &= rounding_corners_flags;
-                window->DrawList->AddRectFilled(ImVec2(x1,y1), ImVec2(x2,y2), col_bg2, rounding_corners_flags_cell ? rounding : 0.0f, rounding_corners_flags_cell);
-            }
-        }
-    }
-    else
-    {
-        window->DrawList->AddRectFilled(p_min, p_max, col, rounding, rounding_corners_flags);
-    }
-}
-
 // Helper for ColorPicker4()
 static void RenderArrowsForVerticalBar(ImDrawList* draw_list, ImVec2 pos, ImVec2 half_sz, float bar_w, float alpha)
 {
@@ -4909,7 +4863,7 @@ bool ImGui::ColorPicker4(const char* label, float col[4], ImGuiColorEditFlags fl
     {
         float alpha = ImSaturate(col[3]);
         ImRect bar1_bb(bar1_pos_x, picker_pos.y, bar1_pos_x + bars_width, picker_pos.y + sv_picker_size);
-        RenderColorRectWithAlphaCheckerboard(bar1_bb.Min, bar1_bb.Max, 0, bar1_bb.GetWidth() / 2.0f, ImVec2(0.0f, 0.0f));
+        RenderColorRectWithAlphaCheckerboard(draw_list, bar1_bb.Min, bar1_bb.Max, 0, bar1_bb.GetWidth() / 2.0f, ImVec2(0.0f, 0.0f));
         draw_list->AddRectFilledMultiColor(bar1_bb.Min, bar1_bb.Max, user_col32_striped_of_alpha, user_col32_striped_of_alpha, user_col32_striped_of_alpha & ~IM_COL32_A_MASK, user_col32_striped_of_alpha & ~IM_COL32_A_MASK);
         float bar1_line_y = IM_ROUND(picker_pos.y + (1.0f - alpha) * sv_picker_size);
         RenderFrameBorder(bar1_bb.Min, bar1_bb.Max, 0.0f);
@@ -4973,15 +4927,15 @@ bool ImGui::ColorButton(const char* desc_id, const ImVec4& col, ImGuiColorEditFl
     if ((flags & ImGuiColorEditFlags_AlphaPreviewHalf) && col_rgb.w < 1.0f)
     {
         float mid_x = IM_ROUND((bb_inner.Min.x + bb_inner.Max.x) * 0.5f);
-        RenderColorRectWithAlphaCheckerboard(ImVec2(bb_inner.Min.x + grid_step, bb_inner.Min.y), bb_inner.Max, GetColorU32(col_rgb), grid_step, ImVec2(-grid_step + off, off), rounding, ImDrawCornerFlags_TopRight| ImDrawCornerFlags_BotRight);
+        RenderColorRectWithAlphaCheckerboard(window->DrawList, ImVec2(bb_inner.Min.x + grid_step, bb_inner.Min.y), bb_inner.Max, GetColorU32(col_rgb), grid_step, ImVec2(-grid_step + off, off), rounding, ImDrawCornerFlags_TopRight| ImDrawCornerFlags_BotRight);
         window->DrawList->AddRectFilled(bb_inner.Min, ImVec2(mid_x, bb_inner.Max.y), GetColorU32(col_rgb_without_alpha), rounding, ImDrawCornerFlags_TopLeft|ImDrawCornerFlags_BotLeft);
     }
     else
     {
         // Because GetColorU32() multiplies by the global style Alpha and we don't want to display a checkerboard if the source code had no alpha
         ImVec4 col_source = (flags & ImGuiColorEditFlags_AlphaPreview) ? col_rgb : col_rgb_without_alpha;
         if (col_source.w < 1.0f)
-            RenderColorRectWithAlphaCheckerboard(bb_inner.Min, bb_inner.Max, GetColorU32(col_source), grid_step, ImVec2(off, off), rounding);
+            RenderColorRectWithAlphaCheckerboard(window->DrawList, bb_inner.Min, bb_inner.Max, GetColorU32(col_source), grid_step, ImVec2(off, off), rounding);
         else
             window->DrawList->AddRectFilled(bb_inner.Min, bb_inner.Max, GetColorU32(col_source), rounding, ImDrawCornerFlags_All);
     }