decouple line height from the font size

Author: cfillion

imgui.cpp

@@ -4012,7 +4012,7 @@ ImGuiContext::ImGuiContext(ImFontAtlas* shared_font_atlas)
     Initialized = false;
     Font = NULL;
     FontBaked = NULL;
-    FontSize = FontSizeBase = FontBakedScale = CurrentDpiScale = 0.0f;
+    FontSize = FontSizeBase = FontBakedScale = LineHeight = CurrentDpiScale = 0.0f;
     FontRasterizerDensity = 1.0f;
     IO.Fonts = shared_font_atlas ? shared_font_atlas : IM_NEW(ImFontAtlas)();
     if (shared_font_atlas == NULL)
@@ -5961,10 +5961,9 @@ ImVec2 ImGui::CalcTextSize(const char* text, const char* text_end, bool hide_tex
         text_display_end = text_end;
 
     ImFont* font = g.Font;
-    const float font_size = g.FontSize;
     if (text == text_display_end)
-        return ImVec2(0.0f, font_size);
-    ImVec2 text_size = font->CalcTextSizeA(font_size, FLT_MAX, wrap_width, text, text_display_end, NULL);
+        return ImVec2(0.0f, g.LineHeight);
+    ImVec2 text_size = font->CalcTextSizeA(g.FontSize, FLT_MAX, wrap_width, text, text_display_end, NULL);
 
     // Round
     // FIXME: This has been here since Dec 2015 (7b0bf230) but down the line we want this out.
@@ -7057,7 +7056,7 @@ void ImGui::RenderWindowTitleBarContents(ImGuiWindow* window, const ImRect& titl
     // FIXME: Would be nice to generalize the subtleties expressed here into reusable code.
     float pad_l = style.FramePadding.x;
     float pad_r = style.FramePadding.x;
-    float button_sz = g.FontSize;
+    float button_sz = g.LineHeight;
     ImVec2 close_button_pos;
     ImVec2 collapse_button_pos;
     if (has_close_button)
@@ -7085,7 +7084,7 @@ void ImGui::RenderWindowTitleBarContents(ImGuiWindow* window, const ImRect& titl
     if (has_close_button)
     {
         g.CurrentItemFlags |= ImGuiItemFlags_NoFocus;
-        if (CloseButton(window->GetID("#CLOSE"), close_button_pos))
+        if (CloseButton(window->GetID("#CLOSE"), close_button_pos, button_sz))
             *p_open = false;
         g.CurrentItemFlags &= ~ImGuiItemFlags_NoFocus;
     }
@@ -7440,8 +7439,8 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         // Lock menu offset so size calculation can use it as menu-bar windows need a minimum size.
         window->DC.MenuBarOffset.x = ImMax(ImMax(window->WindowPadding.x, style.ItemSpacing.x), g.NextWindowData.MenuBarOffsetMinVal.x);
         window->DC.MenuBarOffset.y = g.NextWindowData.MenuBarOffsetMinVal.y;
-        window->TitleBarHeight = (flags & ImGuiWindowFlags_NoTitleBar) ? 0.0f : g.FontSize + g.Style.FramePadding.y * 2.0f;
-        window->MenuBarHeight = (flags & ImGuiWindowFlags_MenuBar) ? window->DC.MenuBarOffset.y + g.FontSize + g.Style.FramePadding.y * 2.0f : 0.0f;
+        window->TitleBarHeight = (flags & ImGuiWindowFlags_NoTitleBar) ? 0.0f : g.LineHeight + g.Style.FramePadding.y * 2.0f;
+        window->MenuBarHeight = (flags & ImGuiWindowFlags_MenuBar) ? window->DC.MenuBarOffset.y + g.LineHeight + g.Style.FramePadding.y * 2.0f : 0.0f;
         window->FontRefSize = g.FontSize; // Lock this to discourage calling window->CalcFontSize() outside of current window.
 
         // Depending on condition we use previous or current window size to compare against contents size to decide if a scrollbar should be visible.
@@ -7574,9 +7573,9 @@ bool ImGui::Begin(const char* name, bool* p_open, ImGuiWindowFlags flags)
         // Large values tend to lead to variety of artifacts and are not recommended.
         window->WindowRounding = (flags & ImGuiWindowFlags_ChildWindow) ? style.ChildRounding : ((flags & ImGuiWindowFlags_Popup) && !(flags & ImGuiWindowFlags_Modal)) ? style.PopupRounding : style.WindowRounding;
 
-        // For windows with title bar or menu bar, we clamp to FrameHeight(FontSize + FramePadding.y * 2.0f) to completely hide artifacts.
+        // For windows with title bar or menu bar, we clamp to FrameHeight(LineHeight + FramePadding.y * 2.0f) to completely hide artifacts.
         //if ((window->Flags & ImGuiWindowFlags_MenuBar) || !(window->Flags & ImGuiWindowFlags_NoTitleBar))
-        //    window->WindowRounding = ImMin(window->WindowRounding, g.FontSize + style.FramePadding.y * 2.0f);
+        //    window->WindowRounding = ImMin(window->WindowRounding, g.LineHeight + style.FramePadding.y * 2.0f);
 
         // Apply window focus (new and reactivated windows are moved to front)
         bool want_focus = false;
@@ -8745,8 +8744,8 @@ void ImGui::UpdateFontsNewFrame()
     g.Font = font;
     g.FontSizeBase = g.Style.FontSizeBase;
     g.FontSize = 0.0f;
-    ImFontStackData font_stack_data = { font, g.Style.FontSizeBase, g.Style.FontSizeBase };           // <--- Will restore FontSize
-    SetCurrentFont(font_stack_data.Font, font_stack_data.FontSizeBeforeScaling, 0.0f); // <--- but use 0.0f to enable scale
+    ImFontStackData font_stack_data = { font, g.Style.FontSizeBase, g.Style.FontSizeBase }; // <--- Will restore FontSize
+    SetCurrentFont(font_stack_data.Font, font_stack_data.FontSizeBeforeScaling, 0.0f);      // <--- but use 0.0f to enable scale
     g.FontStack.push_back(font_stack_data);
     IM_ASSERT(g.Font->IsLoaded());
 }
@@ -8875,6 +8874,7 @@ void ImGui::UpdateCurrentFontSize(float restore_font_size_after_scaling)
         g.Font->CurrentRasterizerDensity = g.FontRasterizerDensity;
     g.FontSize = final_size;
     g.FontBaked = (g.Font != NULL && window != NULL) ? g.Font->GetFontBaked(final_size) : NULL;
+    g.LineHeight = g.FontBaked ? g.FontBaked->LineHeight : g.FontSize;
     g.FontBakedScale = (g.Font != NULL && window != NULL) ? (g.FontSize / g.FontBaked->Size) : 0.0f;
     g.DrawListSharedData.FontSize = g.FontSize;
     g.DrawListSharedData.FontScale = g.FontBakedScale;
@@ -11365,25 +11365,25 @@ ImVec2 ImGui::CalcItemSize(ImVec2 size, float default_w, float default_h)
 float ImGui::GetTextLineHeight()
 {
     ImGuiContext& g = *GImGui;
-    return g.FontSize;
+    return g.LineHeight;
 }
 
 float ImGui::GetTextLineHeightWithSpacing()
 {
     ImGuiContext& g = *GImGui;
-    return g.FontSize + g.Style.ItemSpacing.y;
+    return g.LineHeight + g.Style.ItemSpacing.y;
 }
 
 float ImGui::GetFrameHeight()
 {
     ImGuiContext& g = *GImGui;
-    return g.FontSize + g.Style.FramePadding.y * 2.0f;
+    return g.LineHeight + g.Style.FramePadding.y * 2.0f;
 }
 
 float ImGui::GetFrameHeightWithSpacing()
 {
     ImGuiContext& g = *GImGui;
-    return g.FontSize + g.Style.FramePadding.y * 2.0f + g.Style.ItemSpacing.y;
+    return g.LineHeight + g.Style.FramePadding.y * 2.0f + g.Style.ItemSpacing.y;
 }
 
 ImVec2 ImGui::GetContentRegionAvail()
@@ -16660,8 +16660,7 @@ void ImGui::ShowMetricsWindow(bool* p_open)
             {
                 char buf[32];
                 ImFormatString(buf, IM_ARRAYSIZE(buf), "%d", window->BeginOrderWithinContext);
-                float font_size = GetFontSize();
-                draw_list->AddRectFilled(window->Pos, window->Pos + ImVec2(font_size, font_size), IM_COL32(200, 100, 100, 255));
+                draw_list->AddRectFilled(window->Pos, window->Pos + ImVec2(g.FontSize, g.LineHeight), IM_COL32(200, 100, 100, 255));
                 draw_list->AddText(window->Pos, IM_COL32(255, 255, 255, 255), buf);
             }
         }
@@ -17044,7 +17043,7 @@ void ImGui::DebugNodeFont(ImFont* font)
                     baked->FindGlyph((ImWchar)base);
 
             const int surface_sqrt = (int)ImSqrt((float)baked->MetricsTotalSurface);
-            Text("Ascent: %f, Descent: %f, Ascent-Descent: %f", baked->Ascent, baked->Descent, baked->Ascent - baked->Descent);
+            Text("Ascent: %f, Descent: %f, Ascent-Descent: %f, LineHeight: %f", baked->Ascent, baked->Descent, baked->Ascent - baked->Descent, baked->LineHeight);
             Text("Texture Area: about %d px ~%dx%d px", baked->MetricsTotalSurface, surface_sqrt, surface_sqrt);
             for (int src_n = 0; src_n < font->Sources.Size; src_n++)
             {
@@ -17389,7 +17388,7 @@ void ImGui::ShowDebugLogWindow(bool* p_open)
 {
     ImGuiContext& g = *GImGui;
     if ((g.NextWindowData.HasFlags & ImGuiNextWindowDataFlags_HasSize) == 0)
-        SetNextWindowSize(ImVec2(0.0f, GetFontSize() * 12.0f), ImGuiCond_FirstUseEver);
+        SetNextWindowSize(ImVec2(0.0f, GetTextLineHeight() * 12.0f), ImGuiCond_FirstUseEver);
     if (!Begin("Dear ImGui Debug Log", p_open) || GetCurrentWindow()->BeginCount > 1)
     {
         End();
@@ -17709,7 +17708,7 @@ void ImGui::ShowIDStackToolWindow(bool* p_open)
 {
     ImGuiContext& g = *GImGui;
     if ((g.NextWindowData.HasFlags & ImGuiNextWindowDataFlags_HasSize) == 0)
-        SetNextWindowSize(ImVec2(0.0f, GetFontSize() * 8.0f), ImGuiCond_FirstUseEver);
+        SetNextWindowSize(ImVec2(0.0f, GetTextLineHeight() * 8.0f), ImGuiCond_FirstUseEver);
     if (!Begin("Dear ImGui ID Stack Tool", p_open) || GetCurrentWindow()->BeginCount > 1)
     {
         End();

imgui.h

@@ -3755,6 +3755,7 @@ struct ImFontBaked
 
     // [Internal] Members: Cold
     float                       Ascent, Descent;    // 4+4   // out // Ascent: distance from top to bottom of e.g. 'A' [0..FontSize] (unscaled)
+    float                       LineHeight;         // 4     // out // Vertical distance between two baselines
     unsigned int                MetricsTotalSurface:26;// 3  // out // Total surface in pixels to get an idea of the font rasterization/texture cost (not exact, we approximate the cost of padding between glyphs)
     unsigned int                WantDestroy:1;         // 0  //     // Queued for destroy
     unsigned int                LoadNoFallback:1;      // 0  //     // Disable loading fallback in lower-level calls.

imgui_draw.cpp

@@ -4616,6 +4616,7 @@ static bool ImGui_ImplStbTrueType_FontBakedInit(ImFontAtlas* atlas, ImFontConfig
         stbtt_GetFontVMetrics(&bd_font_data->FontInfo, &unscaled_ascent, &unscaled_descent, &unscaled_line_gap);
         baked->Ascent = ImCeil(unscaled_ascent * scale_for_layout);
         baked->Descent = ImFloor(unscaled_descent * scale_for_layout);
+        baked->LineHeight = baked->Size;
     }
     return true;
 }
@@ -5060,7 +5061,7 @@ void ImFontBaked::ClearOutputData()
     IndexAdvanceX.clear();
     IndexLookup.clear();
     FallbackGlyphIndex = -1;
-    Ascent = Descent = 0.0f;
+    Ascent = Descent = LineHeight = 0.0f;
     MetricsTotalSurface = 0;
 }
 
@@ -5460,8 +5461,8 @@ ImVec2 ImFont::CalcTextSizeA(float size, float max_width, float wrap_width, cons
     if (!text_end)
         text_end = text_begin + ImStrlen(text_begin); // FIXME-OPT: Need to avoid this.
 
-    const float line_height = size;
     ImFontBaked* baked = GetFontBaked(size);
+    const float line_height = baked->LineHeight;
     const float scale = size / baked->Size;
 
     ImVec2 text_size = ImVec2(0, 0);
@@ -5591,9 +5592,9 @@ void ImFont::RenderText(ImDrawList* draw_list, float size, const ImVec2& pos, Im
     if (!text_end)
         text_end = text_begin + ImStrlen(text_begin); // ImGui:: functions generally already provides a valid text_end, so this is merely to handle direct calls.
 
-    const float line_height = size;
     ImFontBaked* baked = GetFontBaked(size);
 
+    const float line_height = baked->LineHeight;
     const float scale = size / baked->Size;
     const float origin_x = x;
     const bool word_wrap_enabled = (wrap_width > 0.0f);

imgui_internal.h

@@ -2145,8 +2145,9 @@ struct ImGuiContext
     ImVector<ImFontAtlas*>  FontAtlases;                        // List of font atlases used by the context (generally only contains g.IO.Fonts aka the main font atlas)
     ImFont*                 Font;                               // Currently bound font. (== FontStack.back().Font)
     ImFontBaked*            FontBaked;                          // Currently bound font at currently bound size. (== Font->GetFontBaked(FontSize))
-    float                   FontSize;                           // Currently bound font size == line height (== FontSizeBase + externals scales applied in the UpdateCurrentFontSize() function).
+    float                   FontSize;                           // Currently bound font size (== FontSizeBase + externals scales applied in the UpdateCurrentFontSize() function).
     float                   FontSizeBase;                       // Font size before scaling == style.FontSizeBase == value passed to PushFont() when specified.
+    float                   LineHeight;                         // Currently bound font's line height (+ externals scales applied in the UpdateCurrentFontSize() function).
     float                   FontBakedScale;                     // == FontBaked->Size / FontSize. Scale factor over baked size. Rarely used nowadays, very often == 1.0f.
     float                   FontRasterizerDensity;              // Current font density. Used by all calls to GetFontBaked().
     float                   CurrentDpiScale;                    // Current window/viewport DpiScale == CurrentViewport->DpiScale
@@ -3551,7 +3552,7 @@ namespace ImGui
     IMGUI_API bool          CheckboxFlags(const char* label, ImU64* flags, ImU64 flags_value);
 
     // Widgets: Window Decorations
-    IMGUI_API bool          CloseButton(ImGuiID id, const ImVec2& pos);
+    IMGUI_API bool          CloseButton(ImGuiID id, ImVec2 pos, float size);
     IMGUI_API bool          CollapseButton(ImGuiID id, const ImVec2& pos);
     IMGUI_API void          Scrollbar(ImGuiAxis axis);
     IMGUI_API bool          ScrollbarEx(const ImRect& bb, ImGuiID id, ImGuiAxis axis, ImS64* p_scroll_v, ImS64 avail_v, ImS64 contents_v, ImDrawFlags draw_rounding_flags = 0);

imgui_tables.cpp

@@ -3075,7 +3075,7 @@ float ImGui::TableGetHeaderRowHeight()
     // In your custom header row you may omit this all together and just call TableNextRow() without a height...
     ImGuiContext& g = *GImGui;
     ImGuiTable* table = g.CurrentTable;
-    float row_height = g.FontSize;
+    float row_height = g.LineHeight;
     for (int column_n = 0; column_n < table->ColumnsCount; column_n++)
         if (IM_BITARRAY_TESTBIT(table->EnabledMaskByIndex, column_n))
             if ((table->Columns[column_n].Flags & ImGuiTableColumnFlags_NoHeaderLabel) == 0)