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Fonts: Amends for support for OpenType SVG fonts using lunasvg (#6591,
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ocornut committed Aug 1, 2023
1 parent 2ad8c60 commit ab490dc
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3 changes: 3 additions & 0 deletions docs/CHANGELOG.txt
Original file line number Diff line number Diff line change
Expand Up @@ -54,6 +54,9 @@ Other changes:

- Fonts: ImFontConfig::OversampleH now defaults to 2 instead of 3, since the
quality increase is largely minimal.
- Fonts, imgui_freetype: Added support to render OpenType SVG fonts using lunasvg.
Requires enabling IMGUI_ENABLE_FREETYPE_LUNASVG along with IMGUI_ENABLE_FREETYPE,
and providing headers/libraries for lunasvg. (#6591, #6607) [@sakiodre]
- ImDrawData: CmdLists[] array is now an ImVector<> owned by ImDrawData rather
than a pointer to internal state.
- This makes it easier for user to create their own or append to an existing draw data.
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14 changes: 6 additions & 8 deletions imconfig.h
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Expand Up @@ -76,18 +76,16 @@
// On Windows you may use vcpkg with 'vcpkg install freetype --triplet=x64-windows' + 'vcpkg integrate install'.
//#define IMGUI_ENABLE_FREETYPE

//---- Use FreeType+lunasvg library to render OpenType SVG fonts (SVGinOT)
// Requires lunasvg headers to be available in the include path + program to be linked with the lunasvg library (not provided).
// Only works in combination with IMGUI_ENABLE_FREETYPE.
// (implementation is based on Freetype's rsvg-port.c which is licensed under CeCILL-C Free Software License Agreement)
//#define IMGUI_ENABLE_FREETYPE_LUNASVG

//---- Use stb_truetype to build and rasterize the font atlas (default)
// The only purpose of this define is if you want force compilation of the stb_truetype backend ALONG with the FreeType backend.
//#define IMGUI_ENABLE_STB_TRUETYPE

//---- Use lunasvg library to render OpenType SVG fonts (SVGinOT)
// Requires lunasvg headers to be available in the include path. Requires program to be compiled with the lunasvg library (not provided).
// See https://github.com/ocornut/imgui/tree/master/misc/freetype
// Only works in combination with IMGUI_ENABLE_FREETYPE.
// The implementation is based on the demo https://gitlab.freedesktop.org/freetype/freetype-demos/-/blob/master/src/rsvg-port.c
// which is licensed under CeCILL-C Free Software License Agreement
//#define IMGUI_ENABLE_FREETYPE_LUNASVG

//---- Define constructor and implicit cast operators to convert back<>forth between your math types and ImVec2/ImVec4.
// This will be inlined as part of ImVec2 and ImVec4 class declarations.
/*
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7 changes: 3 additions & 4 deletions misc/freetype/README.md
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Expand Up @@ -22,7 +22,7 @@ See https://gist.github.com/ocornut/b3a9ecf13502fd818799a452969649ad

### Known issues

- Oversampling settins are ignored but also not so much necessary with the higher quality rendering.
- Oversampling settings are ignored but also not so much necessary with the higher quality rendering.

### Comparison

Expand All @@ -36,10 +36,9 @@ You can use the `ImGuiFreeTypeBuilderFlags_LoadColor` flag to load certain color

![colored glyphs](https://user-images.githubusercontent.com/8225057/106171241-9dc4ba80-6191-11eb-8a69-ca1467b206d1.png)


### Using OpenType SVG fonts (SVGinOT)
- *SVG in Open Type* is a standard by Adobe and Mozilla for color OpenType and Open Font Format fonts. It allows font creators to embed complete SVG files within a font enabling full color and even animations.
- Popular fonts such as [twemoji](https://github.com/13rac1/twemoji-color-font) and fonts made with [scfbuild](https://github.com/13rac1/scfbuild) is SVGinOT
- Requires: [lunasvg](https://github.com/sammycage/lunasvg) v2.3.2 and above
1. Add `#define IMGUI_ENABLE_FREETYPE_OTSVG` in your `imconfig.h`.
2. Get latest lunasvg binaries or build yourself. Under Windows you may use vcpkg with: `vcpkg install lunasvg --triplet=x64-windows`.
1. Add `#define IMGUI_ENABLE_FREETYPE_LUNASVG` in your `imconfig.h`.
2. Get latest lunasvg binaries or build yourself. Under Windows you may use vcpkg with: `vcpkg install lunasvg --triplet=x64-windows`.
104 changes: 43 additions & 61 deletions misc/freetype/imgui_freetype.cpp
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Expand Up @@ -6,14 +6,13 @@

// CHANGELOG
// (minor and older changes stripped away, please see git history for details)
// 2023/07/12: added support for SVG fonts, enable by using '#define IMGUI_ENABLE_FREETYPE_LUNASVG'
// 2023/08/01: added support for SVG fonts, enable by using '#define IMGUI_ENABLE_FREETYPE_LUNASVG' (#6591)
// 2023/01/04: fixed a packing issue which in some occurrences would prevent large amount of glyphs from being packed correctly.
// 2021/08/23: fixed crash when FT_Render_Glyph() fails to render a glyph and returns NULL.
// 2021/03/05: added ImGuiFreeTypeBuilderFlags_Bitmap to load bitmap glyphs.
// 2021/03/02: set 'atlas->TexPixelsUseColors = true' to help some backends with deciding of a prefered texture format.
// 2021/01/28: added support for color-layered glyphs via ImGuiFreeTypeBuilderFlags_LoadColor (require Freetype 2.10+).
// 2021/01/26: simplified integration by using '#define IMGUI_ENABLE_FREETYPE'.
// renamed ImGuiFreeType::XXX flags to ImGuiFreeTypeBuilderFlags_XXX for consistency with other API. removed ImGuiFreeType::BuildFontAtlas().
// 2021/01/26: simplified integration by using '#define IMGUI_ENABLE_FREETYPE'. renamed ImGuiFreeType::XXX flags to ImGuiFreeTypeBuilderFlags_XXX for consistency with other API. removed ImGuiFreeType::BuildFontAtlas().
// 2020/06/04: fix for rare case where FT_Get_Char_Index() succeed but FT_Load_Glyph() fails.
// 2019/02/09: added RasterizerFlags::Monochrome flag to disable font anti-aliasing (combine with ::MonoHinting for best results!)
// 2019/01/15: added support for imgui allocators + added FreeType only override function SetAllocatorFunctions().
Expand Down Expand Up @@ -49,7 +48,9 @@
#include FT_OTSVG_H // <freetype/otsvg.h>
#include FT_BBOX_H // <freetype/ftbbox.h>
#include <lunasvg.h>
#include <memory>
#if !((FREETYPE_MAJOR >= 2) && (FREETYPE_MINOR >= 12))
#error IMGUI_ENABLE_FREETYPE_LUNASVG requires FreeType version >= 2.12
#endif
#endif

#ifdef _MSC_VER
Expand Down Expand Up @@ -78,12 +79,12 @@ static void* (*GImGuiFreeTypeAllocFunc)(size_t size, void* user_data) = ImGuiFre
static void (*GImGuiFreeTypeFreeFunc)(void* ptr, void* user_data) = ImGuiFreeTypeDefaultFreeFunc;
static void* GImGuiFreeTypeAllocatorUserData = nullptr;


// Lunasvg support
#ifdef IMGUI_ENABLE_FREETYPE_LUNASVG
FT_Error ImGuiLunasvgPortInit(FT_Pointer* state);
void ImGuiLunasvgPortFree(FT_Pointer* state);
FT_Error ImGuiLunasvgPortRender(FT_GlyphSlot slot, FT_Pointer* _state);
FT_Error ImGuiLunasvgPortPresetSlot(FT_GlyphSlot slot, FT_Bool cache, FT_Pointer* _state);
static FT_Error ImGuiLunasvgPortInit(FT_Pointer* state);
static void ImGuiLunasvgPortFree(FT_Pointer* state);
static FT_Error ImGuiLunasvgPortRender(FT_GlyphSlot slot, FT_Pointer* _state);
static FT_Error ImGuiLunasvgPortPresetSlot(FT_GlyphSlot slot, FT_Bool cache, FT_Pointer* _state);
#endif

//-------------------------------------------------------------------------
Expand Down Expand Up @@ -260,19 +261,14 @@ namespace

// Need an outline for this to work
FT_GlyphSlot slot = Face->glyph;

#if ((FREETYPE_MAJOR >= 2) && (FREETYPE_MINOR >= 12))
#ifdef IMGUI_ENABLE_FREETYPE_LUNASVG
IM_ASSERT(slot->format == FT_GLYPH_FORMAT_OUTLINE || slot->format == FT_GLYPH_FORMAT_BITMAP || slot->format == FT_GLYPH_FORMAT_SVG);
#else
IM_ASSERT(slot->format != FT_GLYPH_FORMAT_SVG &&
"The font contains SVG glyphs, you'll need to enable IMGUI_ENABLE_FREETYPE_LUNASVG"
"in imconfig.h and install required libraries in order to use this font");
#if ((FREETYPE_MAJOR >= 2) && (FREETYPE_MINOR >= 12))
IM_ASSERT(slot->format != FT_GLYPH_FORMAT_SVG && "The font contains SVG glyphs, you'll need to enable IMGUI_ENABLE_FREETYPE_LUNASVG in imconfig.h and install required libraries in order to use this font");
#endif
IM_ASSERT(slot->format == FT_GLYPH_FORMAT_OUTLINE || slot->format == FT_GLYPH_FORMAT_BITMAP);
#endif // IMGUI_ENABLE_FREETYPE_LUNASVG
#else
IM_ASSERT(slot->format == FT_GLYPH_FORMAT_OUTLINE || slot->format == FT_GLYPH_FORMAT_BITMAP);
#endif // ((FREETYPE_MAJOR >= 2) && (FREETYPE_MINOR >= 12))

// Apply convenience transform (this is not picking from real "Bold"/"Italic" fonts! Merely applying FreeType helper transform. Oblique == Slanting)
if (UserFlags & ImGuiFreeTypeBuilderFlags_Bold)
Expand Down Expand Up @@ -799,15 +795,11 @@ static bool ImFontAtlasBuildWithFreeType(ImFontAtlas* atlas)
FT_Add_Default_Modules(ft_library);

#ifdef IMGUI_ENABLE_FREETYPE_LUNASVG
#if ((FREETYPE_MAJOR >= 2) && (FREETYPE_MINOR >= 12))
// Install svg hooks for FreeType
// https://freetype.org/freetype2/docs/reference/ft2-properties.html#svg-hooks
// https://freetype.org/freetype2/docs/reference/ft2-svg_fonts.html#svg_fonts
SVG_RendererHooks hooks = {ImGuiLunasvgPortInit, ImGuiLunasvgPortFree, ImGuiLunasvgPortRender, ImGuiLunasvgPortPresetSlot};
SVG_RendererHooks hooks = { ImGuiLunasvgPortInit, ImGuiLunasvgPortFree, ImGuiLunasvgPortRender, ImGuiLunasvgPortPresetSlot };
FT_Property_Set(ft_library, "ot-svg", "svg-hooks", &hooks);
#else
IM_ASSERT(!"IMGUI_ENABLE_FREETYPE_LUNASVG requires FreeType version >= 2.12");
#endif // ((FREETYPE_MAJOR >= 2) && (FREETYPE_MINOR >= 12))
#endif // IMGUI_ENABLE_FREETYPE_LUNASVG

bool ret = ImFontAtlasBuildWithFreeTypeEx(ft_library, atlas, atlas->FontBuilderFlags);
Expand All @@ -832,56 +824,51 @@ void ImGuiFreeType::SetAllocatorFunctions(void* (*alloc_func)(size_t sz, void* u

#ifdef IMGUI_ENABLE_FREETYPE_LUNASVG
// For more details, see https://gitlab.freedesktop.org/freetype/freetype-demos/-/blob/master/src/rsvg-port.c
// The original code from the demo is licensed under CeCILL-C Free Software License Agreement
// https://gitlab.freedesktop.org/freetype/freetype/-/blob/master/LICENSE.TXT
typedef struct LunasvgPortState_
// The original code from the demo is licensed under CeCILL-C Free Software License Agreement (https://gitlab.freedesktop.org/freetype/freetype/-/blob/master/LICENSE.TXT)
struct LunasvgPortState
{
FT_Error err = FT_Err_Ok;
FT_Error err = FT_Err_Ok;
lunasvg::Matrix matrix;
std::unique_ptr<lunasvg::Document> svg = nullptr;
lunasvg::Matrix matrix; // Scaled and translated matrix for rendering
} LunasvgPortState, *PLunasvgPortState;
};

FT_Error ImGuiLunasvgPortInit(FT_Pointer* _state)
static FT_Error ImGuiLunasvgPortInit(FT_Pointer* _state)
{
*_state = new LunasvgPortState();
*_state = IM_NEW(LunasvgPortState)();
return FT_Err_Ok;
}

void ImGuiLunasvgPortFree(FT_Pointer* _state)
static void ImGuiLunasvgPortFree(FT_Pointer* _state)
{
delete *_state;
IM_DELETE(*_state);
}

FT_Error ImGuiLunasvgPortRender(FT_GlyphSlot slot, FT_Pointer* _state)
static FT_Error ImGuiLunasvgPortRender(FT_GlyphSlot slot, FT_Pointer* _state)
{
PLunasvgPortState state = *(PLunasvgPortState*)_state;
LunasvgPortState* state = *(LunasvgPortState**)_state;

// If there was an error while loading the svg in
// `ImGuiLunasvgPortPresetSlot`, the renderer hook
// still get called, so just returns the error.
if (state->err != FT_Err_Ok) return state->err;
// If there was an error while loading the svg in ImGuiLunasvgPortPresetSlot(), the renderer hook still get called, so just returns the error.
if (state->err != FT_Err_Ok)
return state->err;

// rows is height, pitch (or stride) equals to width * sizeof(int32)
lunasvg::Bitmap bitmap((uint8_t*)slot->bitmap.buffer, slot->bitmap.width, slot->bitmap.rows, slot->bitmap.pitch);

state->svg->setMatrix(state->svg->matrix().identity()); // Reset the svg matrix to the default value
state->svg->render(bitmap, state->matrix); // state->matrix is already scaled and translated

state->err = FT_Err_Ok;
return state->err;
}

FT_Error ImGuiLunasvgPortPresetSlot(FT_GlyphSlot slot, FT_Bool cache, FT_Pointer* _state)
static FT_Error ImGuiLunasvgPortPresetSlot(FT_GlyphSlot slot, FT_Bool cache, FT_Pointer* _state)
{
FT_SVG_Document document = (FT_SVG_Document)slot->other;
PLunasvgPortState state = *(PLunasvgPortState*)_state;
LunasvgPortState* state = *(LunasvgPortState**)_state;
FT_Size_Metrics& metrics = document->metrics;

// This function is called twice, once in the `FT_Load_Glyph`
// and another right before `ImGuiLunasvgPortRender`.
// If it's the latter, don't do anything because it's
// already done in the former.
if (cache) return state->err;
// This function is called twice, once in the FT_Load_Glyph() and another right before ImGuiLunasvgPortRender().
// If it's the latter, don't do anything because it's // already done in the former.
if (cache)
return state->err;

state->svg = lunasvg::Document::loadFromData((const char*)document->svg_document, document->svg_document_length);
if (state->svg == nullptr)
Expand All @@ -891,7 +878,6 @@ FT_Error ImGuiLunasvgPortPresetSlot(FT_GlyphSlot slot, FT_Bool cache, FT_Pointer
}

lunasvg::Box box = state->svg->box();

double scale = std::min(metrics.x_ppem / box.w, metrics.y_ppem / box.h);
double xx = (double)document->transform.xx / (1 << 16);
double xy = -(double)document->transform.xy / (1 << 16);
Expand All @@ -900,10 +886,8 @@ FT_Error ImGuiLunasvgPortPresetSlot(FT_GlyphSlot slot, FT_Bool cache, FT_Pointer
double x0 = (double)document->delta.x / 64 * box.w / metrics.x_ppem;
double y0 = -(double)document->delta.y / 64 * box.h / metrics.y_ppem;

// This reset the matrix to its default value
state->matrix.identity();

// Scale and transform, we don't translate the svg yet
state->matrix.identity();
state->matrix.scale(scale, scale);
state->matrix.transform(xx, xy, yx, yy, x0, y0);
state->svg->setMatrix(state->matrix);
Expand All @@ -917,24 +901,20 @@ FT_Error ImGuiLunasvgPortPresetSlot(FT_GlyphSlot slot, FT_Bool cache, FT_Pointer
// Calculate the bitmap size
slot->bitmap_left = FT_Int(box.x);
slot->bitmap_top = FT_Int(-box.y);
slot->bitmap.rows = (unsigned int)(ceil(box.h));
slot->bitmap.width = (unsigned int)(ceil(box.w));
slot->bitmap.rows = (unsigned int)(ImCeil((float)box.h));
slot->bitmap.width = (unsigned int)(ImCeil((float)box.w));
slot->bitmap.pitch = slot->bitmap.width * 4;
slot->bitmap.pixel_mode = FT_PIXEL_MODE_BGRA;

// Compute all the bearings and set them correctly. The outline is
// scaled already, we just need to use the bounding box.
// Compute all the bearings and set them correctly. The outline is scaled already, we just need to use the bounding box.
double metrics_width = box.w;
double metrics_height = box.h;
double horiBearingX = box.x;
double horiBearingY = -box.y;

double vertBearingX = slot->metrics.horiBearingX / 64.0 - slot->metrics.horiAdvance / 64.0 / 2.0;
double vertBearingY = (slot->metrics.vertAdvance / 64.0 - slot->metrics.height / 64.0) / 2.0;

slot->metrics.width = FT_Pos(round(metrics_width * 64.0));
slot->metrics.height = FT_Pos(round(metrics_height * 64.0));

slot->metrics.width = FT_Pos(IM_ROUND(metrics_width * 64.0)); // Using IM_ROUND() assume width and height are positive
slot->metrics.height = FT_Pos(IM_ROUND(metrics_height * 64.0));
slot->metrics.horiBearingX = FT_Pos(horiBearingX * 64);
slot->metrics.horiBearingY = FT_Pos(horiBearingY * 64);
slot->metrics.vertBearingX = FT_Pos(vertBearingX * 64);
Expand All @@ -946,7 +926,9 @@ FT_Error ImGuiLunasvgPortPresetSlot(FT_GlyphSlot slot, FT_Bool cache, FT_Pointer
state->err = FT_Err_Ok;
return state->err;
}
#endif // !IMGUI_ENABLE_FREETYPE_LUNASVG

#endif // #ifdef IMGUI_ENABLE_FREETYPE_LUNASVG

//-----------------------------------------------------------------------------

#ifdef __GNUC__
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