Method DebugNodeDrawList

imgui_tiny_app/imgui/imgui.cpp:23138–23230

[DEBUG] Display contents of ImDrawList Note that both 'window' and 'viewport' may be NULL here. Viewport is generally null of destroyed popups which previously owned a viewport.

// [DEBUG] Display contents of ImDrawList
// Note that both 'window' and 'viewport' may be NULL here. Viewport is generally null of destroyed popups which previously owned a viewport.
void ImGui::DebugNodeDrawList(ImGuiWindow* window, ImGuiViewportP* viewport, const ImDrawList* draw_list, const char* label)
{
    ImGuiContext& g = *GImGui;
    ImGuiMetricsConfig* cfg = &g.DebugMetricsConfig;
    int cmd_count = draw_list->CmdBuffer.Size;
    if (cmd_count > 0 && draw_list->CmdBuffer.back().ElemCount == 0 && draw_list->CmdBuffer.back().UserCallback == NULL)
        cmd_count--;
    bool node_open = TreeNode(draw_list, "%s: '%s' %d vtx, %d indices, %d cmds", label, draw_list->_OwnerName ? draw_list->_OwnerName : "", draw_list->VtxBuffer.Size, draw_list->IdxBuffer.Size, cmd_count);
    if (draw_list == GetWindowDrawList())
    {
        SameLine();
        TextColored(ImVec4(1.0f, 0.4f, 0.4f, 1.0f), "CURRENTLY APPENDING"); // Can't display stats for active draw list! (we don't have the data double-buffered)
        if (node_open)
            TreePop();
        return;
    }

    ImDrawList* fg_draw_list = viewport ? GetForegroundDrawList(viewport) : NULL; // Render additional visuals into the top-most draw list
    if (window && IsItemHovered() && fg_draw_list)
        fg_draw_list->AddRect(window->Pos, window->Pos + window->Size, IM_COL32(255, 255, 0, 255));
    if (!node_open)
        return;

    if (window && !window->WasActive)
        TextDisabled("Warning: owning Window is inactive. This DrawList is not being rendered!");

    for (const ImDrawCmd* pcmd = draw_list->CmdBuffer.Data; pcmd < draw_list->CmdBuffer.Data + cmd_count; pcmd++)
    {
        if (pcmd->UserCallback)
        {
            BulletText("Callback %p, user_data %p", pcmd->UserCallback, pcmd->UserCallbackData);
            continue;
        }

        char texid_desc[30];
        FormatTextureRefForDebugDisplay(texid_desc, IM_COUNTOF(texid_desc), pcmd->TexRef);
        char buf[300];
        ImFormatString(buf, IM_COUNTOF(buf), "DrawCmd:%5d tris, Tex %s, ClipRect (%4.0f,%4.0f)-(%4.0f,%4.0f)",
            pcmd->ElemCount / 3, texid_desc, pcmd->ClipRect.x, pcmd->ClipRect.y, pcmd->ClipRect.z, pcmd->ClipRect.w);
        bool pcmd_node_open = TreeNode((void*)(pcmd - draw_list->CmdBuffer.begin()), "%s", buf);
        if (IsItemHovered() && (cfg->ShowDrawCmdMesh || cfg->ShowDrawCmdBoundingBoxes) && fg_draw_list)
            DebugNodeDrawCmdShowMeshAndBoundingBox(fg_draw_list, draw_list, pcmd, cfg->ShowDrawCmdMesh, cfg->ShowDrawCmdBoundingBoxes);
        if (!pcmd_node_open)
            continue;

        // Calculate approximate coverage area (touched pixel count)
        // This will be in pixels squared as long there's no post-scaling happening to the renderer output.
        const ImDrawIdx* idx_buffer = (draw_list->IdxBuffer.Size > 0) ? draw_list->IdxBuffer.Data : NULL;
        const ImDrawVert* vtx_buffer = draw_list->VtxBuffer.Data + pcmd->VtxOffset;
        float total_area = 0.0f;
        for (unsigned int idx_n = pcmd->IdxOffset; idx_n < pcmd->IdxOffset + pcmd->ElemCount; )
        {
            ImVec2 triangle[3];
            for (int n = 0; n < 3; n++, idx_n++)
                triangle[n] = vtx_buffer[idx_buffer ? idx_buffer[idx_n] : idx_n].pos;
            total_area += ImTriangleArea(triangle[0], triangle[1], triangle[2]);
        }