Merge branch '2018-03-font_offset' into master2

imgui.cpp

@@ -251,6 +251,7 @@
  Here is a change-log of API breaking changes, if you are using one of the functions listed, expect to have to fix some code.
  Also read releases logs https://github.com/ocornut/imgui/releases for more details.
 
+ - 2018/XX/XX (1.XX) - ImFont::DisplayOffset.y field defaults to 0 instead of +1.
  - 2018/03/03 (1.60) - Renamed ImGuiStyleVar_Count_ to ImGuiStyleVar_COUNT and ImGuiMouseCursor_Count_ to ImGuiMouseCursor_COUNT for consistency with other public enums.
  - 2018/02/18 (1.60) - BeginDragDropSource(): temporarily removed the optional mouse_button=0 parameter because it is not really usable in many situations at the moment. 
  - 2018/02/16 (1.60) - obsoleted the io.RenderDrawListsFn callback, you can call your graphics engine render function after ImGui::Render(). Use ImGui::GetDrawData() to retrieve the ImDrawData* to display.

imgui.h

@@ -1762,7 +1762,7 @@ struct ImFont
     // Members: Hot ~62/78 bytes
     float                       FontSize;           // <user set>   // Height of characters, set during loading (don't change after loading)
     float                       Scale;              // = 1.f        // Base font scale, multiplied by the per-window font scale which you can adjust with SetFontScale()
-    ImVec2                      DisplayOffset;      // = (0.f,1.f)  // Offset font rendering by xx pixels
+    ImVec2                      DisplayOffset;      // = (0.f,0.f)  // Offset font rendering by xx pixels
     ImVector<ImFontGlyph>       Glyphs;             //              // All glyphs.
     ImVector<float>             IndexAdvanceX;      //              // Sparse. Glyphs->AdvanceX in a directly indexable way (more cache-friendly, for CalcTextSize functions which are often bottleneck in large UI).
     ImVector<unsigned short>    IndexLookup;        //              // Sparse. Index glyphs by Unicode code-point.

imgui_draw.cpp

@@ -1525,6 +1525,7 @@ ImFont* ImFontAtlas::AddFontDefault(const ImFontConfig* font_cfg_template)
 
     const char* ttf_compressed_base85 = GetDefaultCompressedFontDataTTFBase85();
     ImFont* font = AddFontFromMemoryCompressedBase85TTF(ttf_compressed_base85, font_cfg.SizePixels, &font_cfg, GetGlyphRangesDefault());
+    font->DisplayOffset.y = 1.0f;
     return font;
 }
 
@@ -1824,8 +1825,8 @@ bool    ImFontAtlasBuildWithStbTruetype(ImFontAtlas* atlas)
         int unscaled_ascent, unscaled_descent, unscaled_line_gap;
         stbtt_GetFontVMetrics(&tmp.FontInfo, &unscaled_ascent, &unscaled_descent, &unscaled_line_gap);
 
-        const float ascent = unscaled_ascent * font_scale;
-        const float descent = unscaled_descent * font_scale;
+        const float ascent = ImFloor(unscaled_ascent * font_scale + ((unscaled_ascent > 0.0f) ? +1 : -1));
+        const float descent = ImFloor(unscaled_descent * font_scale + ((unscaled_descent > 0.0f) ? +1 : -1));
         ImFontAtlasBuildSetupFont(atlas, dst_font, &cfg, ascent, descent);
         const float off_x = cfg.GlyphOffset.x;
         const float off_y = cfg.GlyphOffset.y + (float)(int)(dst_font->Ascent + 0.5f);
@@ -2139,7 +2140,7 @@ ImFont::ImFont()
 {
     Scale = 1.0f;
     FallbackChar = (ImWchar)'?';
-    DisplayOffset = ImVec2(0.0f, 1.0f);
+    DisplayOffset = ImVec2(0.0f, 0.0f);
     ClearOutputData();
 }