ImFontAtlas: Re-arranging code to simplify implementation of imgui_freetype. (#618)

Author: ocornut

imgui_draw.cpp

@@ -1477,20 +1477,9 @@ bool    ImFontAtlas::Build()
 
         float ascent = unscaled_ascent * font_scale;
         float descent = unscaled_descent * font_scale;
-        if (!cfg.MergeMode)
-        {
-            dst_font->ContainerAtlas = this;
-            dst_font->ConfigData = &cfg;
-            dst_font->ConfigDataCount = 0;
-            dst_font->FontSize = cfg.SizePixels;
-            dst_font->Ascent = ascent;
-            dst_font->Descent = descent;
-            dst_font->Glyphs.resize(0);
-            dst_font->MetricsTotalSurface = 0;
-        }
-        dst_font->ConfigDataCount++;
+        ImFontAtlasBuildSetupFont(this, dst_font, &cfg, ascent, descent);
         float off_x = cfg.GlyphOffset.x;
-        float off_y = cfg.GlyphOffset.y;
+        float off_y = cfg.GlyphOffset.y + (float)(int)(dst_font->Ascent + 0.5f);
 
         dst_font->FallbackGlyph = NULL; // Always clear fallback so FindGlyph can return NULL. It will be set again in BuildLookupTable()
         for (int i = 0; i < tmp.RangesCount; i++)
@@ -1513,11 +1502,16 @@ bool    ImFontAtlas::Build()
                 dst_font->Glyphs.resize(dst_font->Glyphs.Size + 1);
                 ImFont::Glyph& glyph = dst_font->Glyphs.back();
                 glyph.Codepoint = (ImWchar)codepoint;
-                glyph.X0 = q.x0 + off_x; glyph.Y0 = q.y0 + off_y; glyph.X1 = q.x1 + off_x; glyph.Y1 = q.y1 + off_y;
-                glyph.U0 = q.s0; glyph.V0 = q.t0; glyph.U1 = q.s1; glyph.V1 = q.t1;
-                glyph.Y0 += (float)(int)(dst_font->Ascent + 0.5f);
-                glyph.Y1 += (float)(int)(dst_font->Ascent + 0.5f);
+                glyph.X0 = q.x0 + off_x; 
+                glyph.Y0 = q.y0 + off_y; 
+                glyph.X1 = q.x1 + off_x; 
+                glyph.Y1 = q.y1 + off_y;
+                glyph.U0 = q.s0; 
+                glyph.V0 = q.t0; 
+                glyph.U1 = q.s1; 
+                glyph.V1 = q.t1;
                 glyph.XAdvance = (pc.xadvance + cfg.GlyphExtraSpacing.x);  // Bake spacing into XAdvance
+
                 if (cfg.PixelSnapH)
                     glyph.XAdvance = (float)(int)(glyph.XAdvance + 0.5f);
                 dst_font->MetricsTotalSurface += (int)((glyph.U1 - glyph.U0) * TexWidth + 1.99f) * (int)((glyph.V1 - glyph.V0) * TexHeight + 1.99f); // +1 to account for average padding, +0.99 to round
@@ -1544,6 +1538,22 @@ void ImFontAtlasBuildRegisterDefaultCustomRects(ImFontAtlas* atlas)
         atlas->CustomRectRegister(FONT_ATLAS_DEFAULT_TEX_DATA_ID, FONT_ATLAS_DEFAULT_TEX_DATA_W_HALF*2+1, FONT_ATLAS_DEFAULT_TEX_DATA_H);
 }
 
+void ImFontAtlasBuildSetupFont(ImFontAtlas* atlas, ImFont* font, ImFontConfig* font_config, float ascent, float descent)
+{
+    if (!font_config->MergeMode)
+    {
+        font->ContainerAtlas = atlas;
+        font->ConfigData = font_config;
+        font->ConfigDataCount = 0;
+        font->FontSize = font_config->SizePixels;
+        font->Ascent = ascent;
+        font->Descent = descent;
+        font->Glyphs.resize(0);
+        font->MetricsTotalSurface = 0;
+    }
+    font->ConfigDataCount++;
+}
+
 void ImFontAtlasBuildPackCustomRects(ImFontAtlas* atlas, void* pack_context_opaque)
 {
     stbrp_context* pack_context = (stbrp_context*)pack_context_opaque;

imgui_internal.h

@@ -792,8 +792,9 @@ namespace ImGui
 
 } // namespace ImGui
 
-// ImFontAtlas
+// ImFontAtlas internals
 IMGUI_API void              ImFontAtlasBuildRegisterDefaultCustomRects(ImFontAtlas* atlas);
+IMGUI_API void              ImFontAtlasBuildSetupFont(ImFontAtlas* atlas, ImFont* font, ImFontConfig* font_config, float ascent, float descent); 
 IMGUI_API void              ImFontAtlasBuildPackCustomRects(ImFontAtlas* atlas, void* spc);
 IMGUI_API void              ImFontAtlasBuildRenderDefaultTexData(ImFontAtlas* atlas);