Texture-based round corners: Make FIXME consistent so they can be grepped. Tidying and added notes of things to fix.

imgui.cpp

@@ -5547,25 +5547,10 @@ static const ImGuiResizeBorderDef resize_border_def[4] =
 static void AddResizeGrip(ImDrawList* dl, const ImVec2& corner, unsigned int rad, int corners_flags, ImU32 col)
 {
     ImTextureID tex = dl->_Data->Font->ContainerAtlas->TexID;
-    IM_ASSERT(tex == dl->_TextureIdStack.back());  // Use high-level ImGui::PushFont() or low-level ImDrawList::PushTextureId() to change font.
+    IM_ASSERT(tex == dl->_TextureIdStack.back());       // Use high-level ImGui::PushFont() or low-level ImDrawList::PushTextureId() to change font.
-
+    IM_ASSERT(ImIsPowerOfTwo(corners_flags));   // Allow a single corner to be specified here.
-    switch (corners_flags)
-    {
-    case ImDrawFlags_RoundCornersTopLeft:
-    case ImDrawFlags_RoundCornersTopRight:
-    case ImDrawFlags_RoundCornersBottomLeft:
-    case ImDrawFlags_RoundCornersBottomRight:
-        break;
-    default:
-    {
-        IM_ASSERT("Invalid ImDrawCornerFlags for corner quad. {Top,Bot}{Left,Right} pick exactly one of each!");
-        return;
-    }
-    }
 
     const ImVec4& uvs = (*dl->_Data->TexUvRoundCornerFilled)[rad - 1];
-
-    // NOTE: test performance using locals instead of array
     const ImVec2 uv[] =
     {
         ImVec2(ImLerp(uvs.x, uvs.z, 0.5f), ImLerp(uvs.y, uvs.w, 0.5f)),
@@ -5861,7 +5846,7 @@ void ImGui::RenderWindowDecorations(ImGuiWindow* window, const ImRect& title_bar
             {
                 const ImGuiResizeGripDef& grip = resize_grip_def[resize_grip_n];
                 const ImVec2 corner = ImLerp(window->Pos, window->Pos + window->Size, grip.CornerPosN);
-                if (g.IO.KeyAlt)
+                if (g.IO.KeyAlt) // FIXME-ROUNDCORNERS
                 {
                     ImVec2 grip_corner = corner;
                     grip_corner.x += grip.InnerDir.x * window_border_size;

imgui.h

@@ -2833,7 +2833,8 @@ struct ImFontAtlas
     int                         PackIdMouseCursors; // Custom texture rectangle ID for white pixel and mouse cursors
     int                         PackIdLines;        // Custom texture rectangle ID for baked anti-aliased lines
 
-    // FIXME-ROUND-SHAPES: WIP
+    // FIXME-ROUNDCORNERS: WIP
+    // FIXME: avoid so many allocations, statically sized buffer removing an indirection may be beneficial here?
     int                     RoundCornersMaxSize;    // Max pixel size of round corner textures to generate
     ImVector<int>           RoundCornersRectIds;    // Ids of custom rects for round corners indexed by size [0] is 1px, [n] is (n+1)px (index up to RoundCornersMaxSize - 1).
     ImVector<ImVec4>        TexUvRoundCornerFilled; // Texture coordinates to filled round corner quads

imgui_demo.cpp

@@ -257,94 +257,108 @@ static void GetVtxIdxDelta(ImDrawList* dl, int* vtx, int *idx)
     idx_o = idx_n;
 }
 
+// https://github.com/ocornut/imgui/issues/1962
+// FIXME-ROUNDCORNERS: Sizes aren't matching.
+// FIXME-ROUNDCORNERS: Lift the RoundCornersMaxSize limitation, fallback on existing renderer.
+// FIXME-ROUNDCORNERS: Work on reducing filtrate for stroked shapes (may need to trade some cpu/vtx to reduce fill-rate for e.g. simple stroked circle) > https://github.com/ocornut/imgui/issues/1962#issuecomment-411507917
+// FIXME-ROUNDCORNERS: Figure out how to support multiple thickness, might hard-code common steps (1.0, 1.5, 2.0, 3.0), not super satisfactory but may be best
+// FIXME-ROUNDCORNERS: AddCircle* API relying on num_segments may need rework, might obsolete this parameter, or make it 0 default and rely on automatic subdivision similar to style.CurveTessellationTol for Bezier
+// FIXME-ROUNDCORNERS: Intentional "low segment count" shapes (e.g. hexagon) currently achieved with AddCircle may need a new API (AddNgon?)
 static void TestTextureBasedRender()
 {
     ImGuiIO& io = ImGui::GetIO();
+    ImGuiStyle& style = ImGui::GetStyle();
 
-    ImGui::TextUnformatted("Press SHIFT to toggle quads (hold to see them).");
+    ImGui::Begin("tex_round_corners");
-    ImGui::TextUnformatted(io.KeyShift ? "SHIFT ON  -- Rasterized quad circle! w00t! OPTIMIZATION!"
+
-        : "SHIFT OFF -- Regular, boring circle with PathArcToFast.");
+    ImGui::Text("Hold SHIFT to toggle (%s)", io.KeyShift ? "SHIFT ON  -- Using textures." : "SHIFT OFF -- Old method.");
 
     static float radius = io.Fonts->RoundCornersMaxSize * 0.5f;
-    ImGui::SliderFloat("radius", &radius, 0.0f, (float)io.Fonts->RoundCornersMaxSize, "%.0f");
-    ImGui::BeginGroup();
-
     static int segments = 20;
-    ImGui::PushItemWidth(120);
-    ImGui::SliderInt("segments", &segments, 3, 100);
-    ImGui::PopItemWidth();
 
-    int vtx = 0;
+    ImGui::SliderFloat("radius", &radius, 0.0f, (float)io.Fonts->RoundCornersMaxSize, "%.0f");
-    int idx = 0;
+
-    ImDrawList* dl = ImGui::GetWindowDrawList();
+    int vtx_n = 0;
+    int idx_n = 0;
+    ImDrawList* draw_list = ImGui::GetWindowDrawList();
 
     {
-        ImGui::Button("##1", ImVec2(200, 200));
+        ImGui::BeginGroup();
-        GetVtxIdxDelta(dl, &vtx, &idx);
+
-        ImVec2 min = ImGui::GetItemRectMin();
+        ImGui::PushItemWidth(120);
-        ImVec2 size = ImGui::GetItemRectSize();
+        ImGui::SliderInt("segments", &segments, 3, 100);
-        dl->AddCircleFilled(ImVec2(min.x + size.x * 0.5f, min.y + size.y * 0.5f), radius, 0xFFFF00FF, segments);
+        ImGui::PopItemWidth();
-        GetVtxIdxDelta(dl, &vtx, &idx);
+
-        ImGui::Text("AddCircleFilled\n %d vtx, %d idx", vtx, idx);
+        {
+            ImGui::Button("##1", ImVec2(200, 200));
+            GetVtxIdxDelta(draw_list, &vtx_n, &idx_n);
+            ImVec2 min = ImGui::GetItemRectMin();
+            ImVec2 size = ImGui::GetItemRectSize();
+            draw_list->AddCircleFilled(ImVec2(min.x + size.x * 0.5f, min.y + size.y * 0.5f), radius, IM_COL32(255,0,255,255), segments);
+            GetVtxIdxDelta(draw_list, &vtx_n, &idx_n);
+            ImGui::Text("AddCircleFilled\n %d vtx, %d idx", vtx_n, idx_n);
+        }
+        {
+            ImGui::Button("##2", ImVec2(200, 200));
+            GetVtxIdxDelta(draw_list, &vtx_n, &idx_n);
+            ImVec2 min = ImGui::GetItemRectMin();
+            ImVec2 size = ImGui::GetItemRectSize();
+            draw_list->AddCircle(ImVec2(min.x + size.x * 0.5f, min.y + size.y * 0.5f), radius, IM_COL32(255,0,255,255), segments);
+            GetVtxIdxDelta(draw_list, &vtx_n, &idx_n);
+            ImGui::Text("AddCircle\n %d vtx, %d idx", vtx_n, idx_n);
+        }
+        ImGui::EndGroup();
     }
-    {
-        ImGui::Button("##2", ImVec2(200, 200));
-        GetVtxIdxDelta(dl, &vtx, &idx);
-        ImVec2 min = ImGui::GetItemRectMin();
-        ImVec2 size = ImGui::GetItemRectSize();
-        dl->AddCircle(ImVec2(min.x + size.x * 0.5f, min.y + size.y * 0.5f), radius, 0xFFFF00FF, segments);
-        GetVtxIdxDelta(dl, &vtx, &idx);
-        ImGui::Text("AddCircle\n %d vtx, %d idx", vtx, idx);
-    }
-    ImGui::EndGroup();
 
     ImGui::SameLine();
 
-    ImGui::BeginGroup();
-    static bool tl = true, tr = true, bl = true, br = true;
-    ImGui::Checkbox("TL", &tl);
-    ImGui::SameLine(0, 12);
-    ImGui::Checkbox("TR", &tr);
-    ImGui::SameLine(0, 12);
-    ImGui::Checkbox("BL", &bl);
-    ImGui::SameLine(0, 12);
-    ImGui::Checkbox("BR", &br);
-
-    ImDrawFlags flags = 0;
-    flags |= tl ? ImDrawFlags_RoundCornersTopLeft : 0;
-    flags |= tr ? ImDrawFlags_RoundCornersTopRight : 0;
-    flags |= bl ? ImDrawFlags_RoundCornersBottomLeft : 0;
-    flags |= br ? ImDrawFlags_RoundCornersBottomRight : 0;
-    if (flags == 0)
-        flags |= ImDrawFlags_RoundCornersNone;
-
     {
-        ImGui::Button("", ImVec2(200, 200));
+        ImGui::BeginGroup();
-        ImVec2 r_min = ImGui::GetItemRectMin();
-        ImVec2 r_max = ImGui::GetItemRectMax();
 
-        GetVtxIdxDelta(dl, &vtx, &idx);
+        static ImDrawFlags corner_flags = ImDrawFlags_RoundCornersAll;
-        dl->AddRectFilled(r_min, r_max, 0xFFFF00FF, radius, flags);
+        ImGui::CheckboxFlags("TL", (unsigned int*)&corner_flags, ImDrawFlags_RoundCornersTopLeft);
-        GetVtxIdxDelta(dl, &vtx, &idx);
+        ImGui::SameLine();
-        ImGui::Text("AddRectFilled\n %d vtx, %d idx", vtx, idx);
+        ImGui::CheckboxFlags("TR", (unsigned int*)&corner_flags, ImDrawFlags_RoundCornersTopRight);
+        ImGui::SameLine();
+        ImGui::CheckboxFlags("BL", (unsigned int*)&corner_flags, ImDrawFlags_RoundCornersBottomLeft);
+        ImGui::SameLine();
+        ImGui::CheckboxFlags("BR", (unsigned int*)&corner_flags, ImDrawFlags_RoundCornersBottomRight);
+
+        {
+            ImGui::Button("##3", ImVec2(200, 200));
+            ImVec2 r_min = ImGui::GetItemRectMin();
+            ImVec2 r_max = ImGui::GetItemRectMax();
+
+            GetVtxIdxDelta(draw_list, &vtx_n, &idx_n);
+            draw_list->AddRectFilled(r_min, r_max, IM_COL32(255,0,255,255), radius, corner_flags ? corner_flags : ImDrawFlags_RoundCornersNone);
+            GetVtxIdxDelta(draw_list, &vtx_n, &idx_n);
+            ImGui::Text("AddRectFilled\n %d vtx, %d idx", vtx_n, idx_n);
+        }
+        {
+            ImGui::Button("##4", ImVec2(200, 200));
+            ImVec2 r_min = ImGui::GetItemRectMin();
+            ImVec2 r_max = ImGui::GetItemRectMax();
+
+            GetVtxIdxDelta(draw_list, &vtx_n, &idx_n);
+            draw_list->AddRect(r_min, r_max, IM_COL32(255,0,255,255), radius, corner_flags);
+            GetVtxIdxDelta(draw_list, &vtx_n, &idx_n);
+            ImGui::Text("AddRect\n %d vtx, %d idx", vtx_n, idx_n);
+        }
+
+        ImGui::EndGroup();
     }
-    {
-        ImGui::Button("", ImVec2(200, 200));
-        ImVec2 r_min = ImGui::GetItemRectMin();
-        ImVec2 r_max = ImGui::GetItemRectMax();
-
-        GetVtxIdxDelta(dl, &vtx, &idx);
-        dl->AddRect(r_min, r_max, 0xFFFF00FF, radius, flags);
-        GetVtxIdxDelta(dl, &vtx, &idx);
-        ImGui::Text("AddRect\n %d vtx, %d idx", vtx, idx);
-    }
-
-    ImGui::EndGroup();
-
     ImGui::Separator();
 
+    ImGui::Text("Style");
+    ImGui::SliderFloat("FrameRounding", &style.FrameRounding, 0.0f, 100.0f, "%.0f");
+    ImGui::SliderFloat("WindowRounding", &style.WindowRounding, 0.0f, 100.0f, "%.0f");
+
+    // Show atlas
+    ImGui::Text("Atlas");
     ImFontAtlas* atlas = ImGui::GetIO().Fonts;
     ImGui::Image(atlas->TexID, ImVec2((float)atlas->TexWidth, (float)atlas->TexHeight), ImVec2(0, 0), ImVec2(1, 1), ImColor(255, 255, 255, 255), ImColor(255, 255, 255, 128));
+
+    ImGui::End();
 }
 
 //-----------------------------------------------------------------------------

imgui_draw.cpp

@@ -1457,7 +1457,7 @@ inline void AddRoundCornerRect(ImDrawList* draw_list, const ImVec2& a, const ImV
     int vyc = vcc, vxc = vcc, vic = vcc;
     int vyd = vcd, vxd = vcd, vid = vcd;
 
-    // FIXME-ROUND_SHAPES: TODO: find a way of saving vertices/triangles here?
+    // FIXME-ROUNDCORNERS: TODO: find a way of saving vertices/triangles here?
     // currently it's the same cost regardless of how many corners are rounded
 
     if (ba || 1)
@@ -1577,7 +1577,7 @@ void ImDrawList::AddRect(const ImVec2& p_min, const ImVec2& p_max, ImU32 col, fl
     rounding = ImMin(rounding, ImFabs(p_max.y - p_min.y) * (((flags & ImDrawFlags_RoundCornersLeft) == ImDrawFlags_RoundCornersLeft) || ((flags & ImDrawFlags_RoundCornersRight) == ImDrawFlags_RoundCornersRight) ? 0.5f : 1.0f) - 1.0f);
 #endif
 
-    // FIXME-ROUND-SHAPES: NOTE HACK TODO figure out why it's broken on small rounding
+    // FIXME-ROUNDCORNERS: NOTE HACK TODO figure out why it's broken on small rounding
     if (ImGui::GetIO().KeyShift && rounding > 3)
         return AddRoundCornerRect(this, p_min, p_max, col, rounding, flags, /* fill */ false);
 
@@ -1606,7 +1606,7 @@ void ImDrawList::AddRectFilled(const ImVec2& p_min, const ImVec2& p_max, ImU32 c
     }
     else
     {
-        // FIXME-ROUND-SHAPES: NOTE HACK TODO figure out why it's broken on small rounding
+        // FIXME-ROUNDCORNERS: NOTE HACK TODO figure out why it's broken on small rounding
         if (ImGui::GetIO().KeyShift && rounding > 3)
         {
             AddRoundCornerRect(this, p_min, p_max, col, rounding, flags, /* fill */ true);
@@ -1755,7 +1755,7 @@ void ImDrawList::AddCircle(const ImVec2& center, float radius, ImU32 col, int nu
     if ((col & IM_COL32_A_MASK) == 0 || radius <= 0.0f)
         return;
 
-    if (ImGui::GetIO().KeyShift)
+    if (ImGui::GetIO().KeyShift) // FIXME-ROUNDCORNERS
     {
         AddRoundCornerCircle(this, center, radius, col, false);
         return;
@@ -1823,7 +1823,7 @@ void ImDrawList::AddNgonFilled(const ImVec2& center, float radius, ImU32 col, in
     if ((col & IM_COL32_A_MASK) == 0 || num_segments <= 2)
         return;
 
-    if (ImGui::GetIO().KeyShift)
+    if (ImGui::GetIO().KeyShift) // FIXME-ROUNDCORNERS
     {
         AddRoundCornerCircle(this, center, radius, col, true);
         return;
@@ -3073,9 +3073,8 @@ const int          FONT_ATLAS_ROUNDED_CORNER_TEX_PADDING = 2;
 
 static void ImFontAtlasBuildRegisterRoundCornersCustomRects(ImFontAtlas* atlas)
 {
-    if (atlas->RoundCornersRectIds.size() > 0)
+    if (atlas->RoundCornersRectIds.Size > 0)
         return;
-
     if ((atlas->Flags & ImFontAtlasFlags_NoBakedRoundCorners))
         return;
 
@@ -3094,32 +3093,28 @@ static void ImFontAtlasBuildRegisterRoundCornersCustomRects(ImFontAtlas* atlas)
 static void ImFontAtlasBuildRenderRoundCornersTexData(ImFontAtlas* atlas)
 {
     IM_ASSERT(atlas->TexPixelsAlpha8 != NULL);
-    IM_ASSERT(atlas->TexUvRoundCornerFilled.size() == 0);
+    IM_ASSERT(atlas->TexUvRoundCornerFilled.Size == 0);
-    IM_ASSERT(atlas->TexUvRoundCornerStroked.size() == 0);
+    IM_ASSERT(atlas->TexUvRoundCornerStroked.Size == 0);
-
+    if (atlas->Flags & ImFontAtlasFlags_NoBakedRoundCorners)
-    if ((atlas->Flags & ImFontAtlasFlags_NoBakedRoundCorners))
         return;
 
+    // Render the texture
     const int w = atlas->TexWidth;
     const unsigned int max = atlas->RoundCornersMaxSize;
-
+    const int pad = FONT_ATLAS_ROUNDED_CORNER_TEX_PADDING;
-    // Filled
     for (unsigned int stage = 0; stage < 2; stage++)
     {
-        bool filled = stage == 0;
+        const bool filled = (stage == 0);
         for (unsigned int n = 0; n < max; n++)
         {
             const unsigned int id = (filled ? 0 : max) + n;
-            IM_ASSERT(atlas->RoundCornersRectIds.size() > (int) n);
+            IM_ASSERT(atlas->RoundCornersRectIds.Size > (int)n);
             ImFontAtlasCustomRect& r = atlas->CustomRects[atlas->RoundCornersRectIds[id]];
             IM_ASSERT(r.IsPacked());
-
-            const int pad = FONT_ATLAS_ROUNDED_CORNER_TEX_PADDING;
-
             IM_ASSERT(r.Width == n + 1 + pad * 2 && r.Height == n + 1 + pad * 2);
 
             const int radius = (int)(r.Width - pad * 2);
-            const float stroke_width = 1.0f;
+            const float stroke_width = 1.0f; // FIXME-ROUNDCORNERS
 
             for (int y = -pad; y < (int) (radius); y++)
                 for (int x = (filled ? -pad : y); x < (int)(filled ? y + pad : radius); x++)
@@ -3129,10 +3124,12 @@ static void ImFontAtlasBuildRenderRoundCornersTexData(ImFontAtlas* atlas)
                     float alpha = 0.0f;
                     if (filled)
                     {
+                        // Fill
                         alpha = ImClamp(-dist, 0.0f, 1.0f);
                     }
                     else
                     {
+                        // Stroke
                         const float alpha1 = ImClamp(dist + stroke_width, 0.0f, 1.0f);
                         const float alpha2 = ImClamp(dist, 0.0f, 1.0f);
                         alpha = alpha1 - alpha2;

imgui_internal.h

@@ -725,7 +725,7 @@ struct IMGUI_API ImDrawListSharedData
     ImU8            CircleSegmentCounts[64];    // Precomputed segment count for given radius before we calculate it dynamically (to avoid calculation overhead)
     const ImVec4*   TexUvLines;                 // UV of anti-aliased lines in the atlas
 
-    // FIXME-ROUNDSHAPES: WIP + need to remove CircleVtx12 before PR
+    // FIXME-ROUNDCORNERS: WIP + need to remove CircleVtx12 before PR
     ImVector<ImVec4>* TexUvRoundCornerFilled;   // UV of filled round corner quad in the atlas
     ImVector<ImVec4>* TexUvRoundCornerStroked;  // UV of stroked round corner quad in the atlas