Internals: Extracted RenderMouseCursor() out of EndFrame(). Moved to imgui_draw.cpp along with RenderArrowPointingAt(). Comments. (#2013)

imgui.cpp

@@ -4551,7 +4551,7 @@ void ImGui::Render()
         ImGui::EndFrame();
     g.FrameCountRendered = g.FrameCount;
 
-    // Gather windows to render
+    // Gather ImDrawList to render (for each active window)
     g.IO.MetricsRenderVertices = g.IO.MetricsRenderIndices = g.IO.MetricsRenderWindows = 0;
     g.DrawDataBuilder.Clear();
     ImGuiWindow* windows_to_render_front_most[2];
@@ -4569,19 +4569,9 @@ void ImGui::Render()
     g.DrawDataBuilder.FlattenIntoSingleLayer();
 
     // Draw software mouse cursor if requested
-    ImVec2 offset, size, uv[4];
+    if (g.IO.MouseDrawCursor)
-    if (g.IO.MouseDrawCursor && g.IO.Fonts->GetMouseCursorTexData(g.MouseCursor, &offset, &size, &uv[0], &uv[2]))
+        RenderMouseCursor(&g.OverlayDrawList, g.IO.MousePos, g.Style.MouseCursorScale, g.MouseCursor);
-    {
+
-        const ImVec2 pos = g.IO.MousePos - offset;
-        const ImTextureID tex_id = g.IO.Fonts->TexID;
-        const float sc = g.Style.MouseCursorScale;
-        g.OverlayDrawList.PushTextureID(tex_id);
-        g.OverlayDrawList.AddImage(tex_id, pos + ImVec2(1,0)*sc, pos+ImVec2(1,0)*sc + size*sc, uv[2], uv[3], IM_COL32(0,0,0,48));        // Shadow
-        g.OverlayDrawList.AddImage(tex_id, pos + ImVec2(2,0)*sc, pos+ImVec2(2,0)*sc + size*sc, uv[2], uv[3], IM_COL32(0,0,0,48));        // Shadow
-        g.OverlayDrawList.AddImage(tex_id, pos,                  pos + size*sc,                uv[2], uv[3], IM_COL32(0,0,0,255));       // Black border
-        g.OverlayDrawList.AddImage(tex_id, pos,                  pos + size*sc,                uv[0], uv[1], IM_COL32(255,255,255,255)); // White fill
-        g.OverlayDrawList.PopTextureID();
-    }
     if (!g.OverlayDrawList.VtxBuffer.empty())
         AddDrawListToDrawData(&g.DrawDataBuilder.Layers[0], &g.OverlayDrawList);
 
@@ -4787,19 +4777,6 @@ void ImGui::RenderFrameBorder(ImVec2 p_min, ImVec2 p_max, float rounding)
     }
 }
 
-// Render an arrow. 'pos' is position of the arrow tip. half_sz.x is length from base to tip. half_sz.y is length on each side.
-void ImGui::RenderArrowPointingAt(ImDrawList* draw_list, ImVec2 pos, ImVec2 half_sz, ImGuiDir direction, ImU32 col)
-{
-    switch (direction)
-    {
-    case ImGuiDir_Left:  draw_list->AddTriangleFilled(ImVec2(pos.x + half_sz.x, pos.y - half_sz.y), ImVec2(pos.x + half_sz.x, pos.y + half_sz.y), pos, col); return;
-    case ImGuiDir_Right: draw_list->AddTriangleFilled(ImVec2(pos.x - half_sz.x, pos.y + half_sz.y), ImVec2(pos.x - half_sz.x, pos.y - half_sz.y), pos, col); return;
-    case ImGuiDir_Up:    draw_list->AddTriangleFilled(ImVec2(pos.x + half_sz.x, pos.y + half_sz.y), ImVec2(pos.x - half_sz.x, pos.y + half_sz.y), pos, col); return;
-    case ImGuiDir_Down:  draw_list->AddTriangleFilled(ImVec2(pos.x - half_sz.x, pos.y - half_sz.y), ImVec2(pos.x + half_sz.x, pos.y - half_sz.y), pos, col); return;
-    case ImGuiDir_None: case ImGuiDir_COUNT: break; // Fix warnings
-    }
-}
-
 // 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
 void ImGui::RenderArrow(ImVec2 p_min, ImGuiDir dir, float scale)
 {

imgui_draw.cpp

@@ -6,6 +6,7 @@
 // - ImDrawList
 // - ImDrawData
 // - ImFontAtlas
+// - Internal Render Helpers
 // - ImFont
 // - Default font data
 
@@ -2786,8 +2787,51 @@ void ImFont::RenderText(ImDrawList* draw_list, float size, ImVec2 pos, ImU32 col
 }
 
 //-----------------------------------------------------------------------------
-// Internals Drawing Helpers
+// Internals Render Helpers
+// (progressively moved from imgui.cpp to here when they are redesigned to stop accessing ImGui global state)
 //-----------------------------------------------------------------------------
+// RenderMouseCursor()
+// RenderArrowPointingAt()
+// RenderRectFilledRangeH()
+//-----------------------------------------------------------------------------
+
+void ImGui::RenderMouseCursor(ImDrawList* draw_list, ImVec2 pos, float scale, ImGuiMouseCursor mouse_cursor)
+{
+    if (mouse_cursor == ImGuiMouseCursor_None)
+        return;
+    IM_ASSERT(mouse_cursor > ImGuiMouseCursor_None && mouse_cursor < ImGuiMouseCursor_COUNT);
+
+    const ImU32 col_shadow = IM_COL32(0, 0, 0, 48);
+    const ImU32 col_border = IM_COL32(0, 0, 0, 255);          // Black
+    const ImU32 col_fill   = IM_COL32(255, 255, 255, 255);    // White
+
+    ImFontAtlas* font_atlas = draw_list->_Data->Font->ContainerAtlas;
+    ImVec2 offset, size, uv[4];
+    if (font_atlas->GetMouseCursorTexData(mouse_cursor, &offset, &size, &uv[0], &uv[2]))
+    {
+        pos -= offset;
+        const ImTextureID tex_id = font_atlas->TexID;
+        draw_list->PushTextureID(tex_id);
+        draw_list->AddImage(tex_id, pos + ImVec2(1,0)*scale, pos + ImVec2(1,0)*scale + size*scale, uv[2], uv[3], col_shadow);
+        draw_list->AddImage(tex_id, pos + ImVec2(2,0)*scale, pos + ImVec2(2,0)*scale + size*scale, uv[2], uv[3], col_shadow);
+        draw_list->AddImage(tex_id, pos,                     pos + size*scale,                     uv[2], uv[3], col_border);
+        draw_list->AddImage(tex_id, pos,                     pos + size*scale,                     uv[0], uv[1], col_fill);
+        draw_list->PopTextureID();
+    }
+}
+
+// Render an arrow. 'pos' is position of the arrow tip. half_sz.x is length from base to tip. half_sz.y is length on each side.
+void ImGui::RenderArrowPointingAt(ImDrawList* draw_list, ImVec2 pos, ImVec2 half_sz, ImGuiDir direction, ImU32 col)
+{
+    switch (direction)
+    {
+    case ImGuiDir_Left:  draw_list->AddTriangleFilled(ImVec2(pos.x + half_sz.x, pos.y - half_sz.y), ImVec2(pos.x + half_sz.x, pos.y + half_sz.y), pos, col); return;
+    case ImGuiDir_Right: draw_list->AddTriangleFilled(ImVec2(pos.x - half_sz.x, pos.y + half_sz.y), ImVec2(pos.x - half_sz.x, pos.y - half_sz.y), pos, col); return;
+    case ImGuiDir_Up:    draw_list->AddTriangleFilled(ImVec2(pos.x + half_sz.x, pos.y + half_sz.y), ImVec2(pos.x - half_sz.x, pos.y + half_sz.y), pos, col); return;
+    case ImGuiDir_Down:  draw_list->AddTriangleFilled(ImVec2(pos.x - half_sz.x, pos.y - half_sz.y), ImVec2(pos.x + half_sz.x, pos.y - half_sz.y), pos, col); return;
+    case ImGuiDir_None: case ImGuiDir_COUNT: break; // Fix warnings
+    }
+}
 
 static inline float ImAcos01(float x)
 {

imgui_internal.h

@@ -1166,7 +1166,7 @@ namespace ImGui
 
     // Render helpers
     // AVOID USING OUTSIDE OF IMGUI.CPP! NOT FOR PUBLIC CONSUMPTION. THOSE FUNCTIONS ARE A MESS. THEIR SIGNATURE AND BEHAVIOR WILL CHANGE, THEY NEED TO BE REFACTORED INTO SOMETHING DECENT.
-    // NB: All position are in absolute pixels coordinates (never using window coordinates internally)
+    // NB: All position are in absolute pixels coordinates (we are never using window coordinates internally)
     IMGUI_API void          RenderText(ImVec2 pos, const char* text, const char* text_end = NULL, bool hide_text_after_hash = true);
     IMGUI_API void          RenderTextWrapped(ImVec2 pos, const char* text, const char* text_end, float wrap_width);
     IMGUI_API void          RenderTextClipped(const ImVec2& pos_min, const ImVec2& pos_max, const char* text, const char* text_end, const ImVec2* text_size_if_known, const ImVec2& align = ImVec2(0,0), const ImRect* clip_rect = NULL);
@@ -1174,13 +1174,16 @@ namespace ImGui
     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          RenderArrow(ImVec2 pos, ImGuiDir dir, float scale = 1.0f);
-    IMGUI_API void          RenderArrowPointingAt(ImDrawList* draw_list, ImVec2 pos, ImVec2 half_sz, ImGuiDir direction, ImU32 col);
     IMGUI_API void          RenderBullet(ImVec2 pos);
     IMGUI_API void          RenderCheckMark(ImVec2 pos, ImU32 col, float sz);
     IMGUI_API void          RenderNavHighlight(const ImRect& bb, ImGuiID id, ImGuiNavHighlightFlags flags = ImGuiNavHighlightFlags_TypeDefault); // Navigation highlight
-    IMGUI_API void          RenderRectFilledRangeH(ImDrawList* draw_list, const ImRect& rect, ImU32 col, float x_start_norm, float x_end_norm, float rounding);
     IMGUI_API const char*   FindRenderedTextEnd(const char* text, const char* text_end = NULL); // Find the optional ## from which we stop displaying text.
 
+    // Render helpers (those functions don't access any ImGui state!)
+    IMGUI_API void          RenderMouseCursor(ImDrawList* draw_list, ImVec2 pos, float scale, ImGuiMouseCursor mouse_cursor = ImGuiMouseCursor_Arrow);
+    IMGUI_API void          RenderArrowPointingAt(ImDrawList* draw_list, ImVec2 pos, ImVec2 half_sz, ImGuiDir direction, ImU32 col);
+    IMGUI_API void          RenderRectFilledRangeH(ImDrawList* draw_list, const ImRect& rect, ImU32 col, float x_start_norm, float x_end_norm, float rounding);
+
     // Widgets
     IMGUI_API bool          ButtonEx(const char* label, const ImVec2& size_arg = ImVec2(0,0), ImGuiButtonFlags flags = 0);
     IMGUI_API bool          CloseButton(ImGuiID id, const ImVec2& pos, float radius);