Internal: Begin: Update rectangles before Scrollbar() which now uses them. Fixes 39eeda0.

imgui.cpp

@@ -5307,6 +5307,40 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         else
             window->ItemWidthDefault = (float)(int)(g.FontSize * 16.0f);
 
+        // Store a backup of SizeFull which we will use next frame to decide if we need scrollbars.
+        window->SizeFullAtLastBegin = window->SizeFull;
+
+        // UPDATE RECTANGLES
+
+        // Update various regions. Variables they depends on are set above in this function.
+        // FIXME: window->ContentsRegionRect.Max is currently very misleading / partly faulty, but some BeginChild() patterns relies on it.
+        // NB: WindowBorderSize is included in WindowPadding _and_ ScrollbarSizes so we need to cancel one out.
+        window->ContentsRegionRect.Min.x = window->Pos.x - window->Scroll.x + window->WindowPadding.x;
+        window->ContentsRegionRect.Min.y = window->Pos.y - window->Scroll.y + window->WindowPadding.y + window->TitleBarHeight() + window->MenuBarHeight();
+        window->ContentsRegionRect.Max.x = window->Pos.x - window->Scroll.x - window->WindowPadding.x + (window->SizeContentsExplicit.x != 0.0f ? window->SizeContentsExplicit.x : (window->Size.x - window->ScrollbarSizes.x + ImMin(window->ScrollbarSizes.x, window->WindowBorderSize)));
+        window->ContentsRegionRect.Max.y = window->Pos.y - window->Scroll.y - window->WindowPadding.y + (window->SizeContentsExplicit.y != 0.0f ? window->SizeContentsExplicit.y : (window->Size.y - window->ScrollbarSizes.y + ImMin(window->ScrollbarSizes.y, window->WindowBorderSize)));
+
+        // Save clipped aabb so we can access it in constant-time in FindHoveredWindow()
+        window->OuterRectClipped = window->Rect();
+        window->OuterRectClipped.ClipWith(window->ClipRect);
+
+        // Inner rectangle
+        // We set this up after processing the resize grip so that our clip rectangle doesn't lag by a frame
+        // Note that if our window is collapsed we will end up with an inverted (~null) clipping rectangle which is the correct behavior.
+        const ImRect title_bar_rect = window->TitleBarRect();
+        window->InnerMainRect.Min.x = title_bar_rect.Min.x + window->WindowBorderSize;
+        window->InnerMainRect.Min.y = title_bar_rect.Max.y + window->MenuBarHeight() + (((flags & ImGuiWindowFlags_MenuBar) || !(flags & ImGuiWindowFlags_NoTitleBar)) ? style.FrameBorderSize : window->WindowBorderSize);
+        window->InnerMainRect.Max.x = window->Pos.x + window->Size.x - ImMax(window->ScrollbarSizes.x, window->WindowBorderSize);
+        window->InnerMainRect.Max.y = window->Pos.y + window->Size.y - ImMax(window->ScrollbarSizes.y, window->WindowBorderSize);
+
+        // Inner clipping rectangle will extend a little bit outside the work region.
+        // This is to allow e.g. Selectable or CollapsingHeader or some separators to cover that space.
+        // Force round operator last to ensure that e.g. (int)(max.x-min.x) in user's render code produce correct result.
+        window->InnerClipRect.Min.x = ImFloor(0.5f + window->InnerMainRect.Min.x + ImMax(0.0f, ImFloor(window->WindowPadding.x * 0.5f - window->WindowBorderSize)));
+        window->InnerClipRect.Min.y = ImFloor(0.5f + window->InnerMainRect.Min.y);
+        window->InnerClipRect.Max.x = ImFloor(0.5f + window->InnerMainRect.Max.x - ImMax(0.0f, ImFloor(window->WindowPadding.x * 0.5f - window->WindowBorderSize)));
+        window->InnerClipRect.Max.y = ImFloor(0.5f + window->InnerMainRect.Max.y);
+
         // DRAWING
 
         // Setup draw list and outer clipping rectangle
@@ -5342,7 +5376,6 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         const float window_border_size = window->WindowBorderSize;
         const ImGuiWindow* window_to_highlight = g.NavWindowingTarget ? g.NavWindowingTarget : g.NavWindow;
         const bool title_bar_is_highlight = want_focus || (window_to_highlight && window->RootWindowForTitleBarHighlight == window_to_highlight->RootWindowForTitleBarHighlight);
-        const ImRect title_bar_rect = window->TitleBarRect();
         if (window->Collapsed)
         {
             // Title bar only
@@ -5422,37 +5455,6 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
             window->DrawList->AddRect(bb.Min, bb.Max, GetColorU32(ImGuiCol_NavWindowingHighlight, g.NavWindowingHighlightAlpha), rounding, ~0, 3.0f);
         }
 
-        // Store a backup of SizeFull which we will use next frame to decide if we need scrollbars.
-        window->SizeFullAtLastBegin = window->SizeFull;
-
-        // Update various regions. Variables they depends on are set above in this function.
-        // FIXME: window->ContentsRegionRect.Max is currently very misleading / partly faulty, but some BeginChild() patterns relies on it.
-        // NB: WindowBorderSize is included in WindowPadding _and_ ScrollbarSizes so we need to cancel one out.
-        window->ContentsRegionRect.Min.x = window->Pos.x - window->Scroll.x + window->WindowPadding.x;
-        window->ContentsRegionRect.Min.y = window->Pos.y - window->Scroll.y + window->WindowPadding.y + window->TitleBarHeight() + window->MenuBarHeight();
-        window->ContentsRegionRect.Max.x = window->Pos.x - window->Scroll.x - window->WindowPadding.x + (window->SizeContentsExplicit.x != 0.0f ? window->SizeContentsExplicit.x : (window->Size.x - window->ScrollbarSizes.x + ImMin(window->ScrollbarSizes.x, window->WindowBorderSize)));
-        window->ContentsRegionRect.Max.y = window->Pos.y - window->Scroll.y - window->WindowPadding.y + (window->SizeContentsExplicit.y != 0.0f ? window->SizeContentsExplicit.y : (window->Size.y - window->ScrollbarSizes.y + ImMin(window->ScrollbarSizes.y, window->WindowBorderSize)));
-
-        // Save clipped aabb so we can access it in constant-time in FindHoveredWindow()
-        window->OuterRectClipped = window->Rect();
-        window->OuterRectClipped.ClipWith(window->ClipRect);
-
-        // Inner rectangle
-        // We set this up after processing the resize grip so that our clip rectangle doesn't lag by a frame
-        // Note that if our window is collapsed we will end up with an inverted (~null) clipping rectangle which is the correct behavior.
-        window->InnerMainRect.Min.x = title_bar_rect.Min.x + window->WindowBorderSize;
-        window->InnerMainRect.Min.y = title_bar_rect.Max.y + window->MenuBarHeight() + (((flags & ImGuiWindowFlags_MenuBar) || !(flags & ImGuiWindowFlags_NoTitleBar)) ? style.FrameBorderSize : window->WindowBorderSize);
-        window->InnerMainRect.Max.x = window->Pos.x + window->Size.x - ImMax(window->ScrollbarSizes.x, window->WindowBorderSize);
-        window->InnerMainRect.Max.y = window->Pos.y + window->Size.y - ImMax(window->ScrollbarSizes.y, window->WindowBorderSize);
-
-        // Inner clipping rectangle will extend a little bit outside the work region.
-        // This is to allow e.g. Selectable or CollapsingHeader or some separators to cover that space.
-        // Force round operator last to ensure that e.g. (int)(max.x-min.x) in user's render code produce correct result.
-        window->InnerClipRect.Min.x = ImFloor(0.5f + window->InnerMainRect.Min.x + ImMax(0.0f, ImFloor(window->WindowPadding.x * 0.5f - window->WindowBorderSize)));
-        window->InnerClipRect.Min.y = ImFloor(0.5f + window->InnerMainRect.Min.y);
-        window->InnerClipRect.Max.x = ImFloor(0.5f + window->InnerMainRect.Max.x - ImMax(0.0f, ImFloor(window->WindowPadding.x * 0.5f - window->WindowBorderSize)));
-        window->InnerClipRect.Max.y = ImFloor(0.5f + window->InnerMainRect.Max.y);
-
         // Setup drawing context
         // (NB: That term "drawing context / DC" lost its meaning a long time ago. Initially was meant to hold transient data only. Nowadays difference between window-> and window->DC-> is dubious.)
         window->DC.Indent.x = 0.0f + window->WindowPadding.x - window->Scroll.x;