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imstb_truetype.h
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imstb_truetype.h
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// [DEAR IMGUI]
// This is a slightly modified version of stb_truetype.h 1.20.
// Mostly fixing for compiler and static analyzer warnings.
// Grep for [DEAR IMGUI] to find the changes.
// stb_truetype.h - v1.20 - public domain
// authored from 2009-2016 by Sean Barrett / RAD Game Tools
//
// This library processes TrueType files:
// parse files
// extract glyph metrics
// extract glyph shapes
// render glyphs to one-channel bitmaps with antialiasing (box filter)
// render glyphs to one-channel SDF bitmaps (signed-distance field/function)
//
// Todo:
// non-MS cmaps
// crashproof on bad data
// hinting? (no longer patented)
// cleartype-style AA?
// optimize: use simple memory allocator for intermediates
// optimize: build edge-list directly from curves
// optimize: rasterize directly from curves?
//
// ADDITIONAL CONTRIBUTORS
//
// Mikko Mononen: compound shape support, more cmap formats
// Tor Andersson: kerning, subpixel rendering
// Dougall Johnson: OpenType / Type 2 font handling
// Daniel Ribeiro Maciel: basic GPOS-based kerning
//
// Misc other:
// Ryan Gordon
// Simon Glass
// github:IntellectualKitty
// Imanol Celaya
// Daniel Ribeiro Maciel
//
// Bug/warning reports/fixes:
// "Zer" on mollyrocket Fabian "ryg" Giesen
// Cass Everitt Martins Mozeiko
// stoiko (Haemimont Games) Cap Petschulat
// Brian Hook Omar Cornut
// Walter van Niftrik github:aloucks
// David Gow Peter LaValle
// David Given Sergey Popov
// Ivan-Assen Ivanov Giumo X. Clanjor
// Anthony Pesch Higor Euripedes
// Johan Duparc Thomas Fields
// Hou Qiming Derek Vinyard
// Rob Loach Cort Stratton
// Kenney Phillis Jr. github:oyvindjam
// Brian Costabile github:vassvik
//
// VERSION HISTORY
//
// 1.20 (2019-02-07) PackFontRange skips missing codepoints; GetScaleFontVMetrics()
// 1.19 (2018-02-11) GPOS kerning, STBTT_fmod
// 1.18 (2018-01-29) add missing function
// 1.17 (2017-07-23) make more arguments const; doc fix
// 1.16 (2017-07-12) SDF support
// 1.15 (2017-03-03) make more arguments const
// 1.14 (2017-01-16) num-fonts-in-TTC function
// 1.13 (2017-01-02) support OpenType fonts, certain Apple fonts
// 1.12 (2016-10-25) suppress warnings about casting away const with -Wcast-qual
// 1.11 (2016-04-02) fix unused-variable warning
// 1.10 (2016-04-02) user-defined fabs(); rare memory leak; remove duplicate typedef
// 1.09 (2016-01-16) warning fix; avoid crash on outofmem; use allocation userdata properly
// 1.08 (2015-09-13) document stbtt_Rasterize(); fixes for vertical & horizontal edges
// 1.07 (2015-08-01) allow PackFontRanges to accept arrays of sparse codepoints;
// variant PackFontRanges to pack and render in separate phases;
// fix stbtt_GetFontOFfsetForIndex (never worked for non-0 input?);
// fixed an assert() bug in the new rasterizer
// replace assert() with STBTT_assert() in new rasterizer
//
// Full history can be found at the end of this file.
//
// LICENSE
//
// See end of file for license information.
//
// USAGE
//
// Include this file in whatever places need to refer to it. In ONE C/C++
// file, write:
// #define STB_TRUETYPE_IMPLEMENTATION
// before the #include of this file. This expands out the actual
// implementation into that C/C++ file.
//
// To make the implementation private to the file that generates the implementation,
// #define STBTT_STATIC
//
// Simple 3D API (don't ship this, but it's fine for tools and quick start)
// stbtt_BakeFontBitmap() -- bake a font to a bitmap for use as texture
// stbtt_GetBakedQuad() -- compute quad to draw for a given char
//
// Improved 3D API (more shippable):
// #include "stb_rect_pack.h" -- optional, but you really want it
// stbtt_PackBegin()
// stbtt_PackSetOversampling() -- for improved quality on small fonts
// stbtt_PackFontRanges() -- pack and renders
// stbtt_PackEnd()
// stbtt_GetPackedQuad()
//
// "Load" a font file from a memory buffer (you have to keep the buffer loaded)
// stbtt_InitFont()
// stbtt_GetFontOffsetForIndex() -- indexing for TTC font collections
// stbtt_GetNumberOfFonts() -- number of fonts for TTC font collections
//
// Render a unicode codepoint to a bitmap
// stbtt_GetCodepointBitmap() -- allocates and returns a bitmap
// stbtt_MakeCodepointBitmap() -- renders into bitmap you provide
// stbtt_GetCodepointBitmapBox() -- how big the bitmap must be
//
// Character advance/positioning
// stbtt_GetCodepointHMetrics()
// stbtt_GetFontVMetrics()
// stbtt_GetFontVMetricsOS2()
// stbtt_GetCodepointKernAdvance()
//
// Starting with version 1.06, the rasterizer was replaced with a new,
// faster and generally-more-precise rasterizer. The new rasterizer more
// accurately measures pixel coverage for anti-aliasing, except in the case
// where multiple shapes overlap, in which case it overestimates the AA pixel
// coverage. Thus, anti-aliasing of intersecting shapes may look wrong. If
// this turns out to be a problem, you can re-enable the old rasterizer with
// #define STBTT_RASTERIZER_VERSION 1
// which will incur about a 15% speed hit.
//
// ADDITIONAL DOCUMENTATION
//
// Immediately after this block comment are a series of sample programs.
//
// After the sample programs is the "header file" section. This section
// includes documentation for each API function.
//
// Some important concepts to understand to use this library:
//
// Codepoint
// Characters are defined by unicode codepoints, e.g. 65 is
// uppercase A, 231 is lowercase c with a cedilla, 0x7e30 is
// the hiragana for "ma".
//
// Glyph
// A visual character shape (every codepoint is rendered as
// some glyph)
//
// Glyph index
// A font-specific integer ID representing a glyph
//
// Baseline
// Glyph shapes are defined relative to a baseline, which is the
// bottom of uppercase characters. Characters extend both above
// and below the baseline.
//
// Current Point
// As you draw text to the screen, you keep track of a "current point"
// which is the origin of each character. The current point's vertical
// position is the baseline. Even "baked fonts" use this model.
//
// Vertical Font Metrics
// The vertical qualities of the font, used to vertically position
// and space the characters. See docs for stbtt_GetFontVMetrics.
//
// Font Size in Pixels or Points
// The preferred interface for specifying font sizes in stb_truetype
// is to specify how tall the font's vertical extent should be in pixels.
// If that sounds good enough, skip the next paragraph.
//
// Most font APIs instead use "points", which are a common typographic
// measurement for describing font size, defined as 72 points per inch.
// stb_truetype provides a point API for compatibility. However, true
// "per inch" conventions don't make much sense on computer displays
// since different monitors have different number of pixels per
// inch. For example, Windows traditionally uses a convention that
// there are 96 pixels per inch, thus making 'inch' measurements have
// nothing to do with inches, and thus effectively defining a point to
// be 1.333 pixels. Additionally, the TrueType font data provides
// an explicit scale factor to scale a given font's glyphs to points,
// but the author has observed that this scale factor is often wrong
// for non-commercial fonts, thus making fonts scaled in points
// according to the TrueType spec incoherently sized in practice.
//
// DETAILED USAGE:
//
// Scale:
// Select how high you want the font to be, in points or pixels.
// Call ScaleForPixelHeight or ScaleForMappingEmToPixels to compute
// a scale factor SF that will be used by all other functions.
//
// Baseline:
// You need to select a y-coordinate that is the baseline of where
// your text will appear. Call GetFontBoundingBox to get the baseline-relative
// bounding box for all characters. SF*-y0 will be the distance in pixels
// that the worst-case character could extend above the baseline, so if
// you want the top edge of characters to appear at the top of the
// screen where y=0, then you would set the baseline to SF*-y0.
//
// Current point:
// Set the current point where the first character will appear. The
// first character could extend left of the current point; this is font
// dependent. You can either choose a current point that is the leftmost
// point and hope, or add some padding, or check the bounding box or
// left-side-bearing of the first character to be displayed and set
// the current point based on that.
//
// Displaying a character:
// Compute the bounding box of the character. It will contain signed values
// relative to <current_point, baseline>. I.e. if it returns x0,y0,x1,y1,
// then the character should be displayed in the rectangle from
// <current_point+SF*x0, baseline+SF*y0> to <current_point+SF*x1,baseline+SF*y1).
//
// Advancing for the next character:
// Call GlyphHMetrics, and compute 'current_point += SF * advance'.
//
//
// ADVANCED USAGE
//
// Quality:
//
// - Use the functions with Subpixel at the end to allow your characters
// to have subpixel positioning. Since the font is anti-aliased, not
// hinted, this is very import for quality. (This is not possible with
// baked fonts.)
//
// - Kerning is now supported, and if you're supporting subpixel rendering
// then kerning is worth using to give your text a polished look.
//
// Performance:
//
// - Convert Unicode codepoints to glyph indexes and operate on the glyphs;
// if you don't do this, stb_truetype is forced to do the conversion on
// every call.
//
// - There are a lot of memory allocations. We should modify it to take
// a temp buffer and allocate from the temp buffer (without freeing),
// should help performance a lot.
//
// NOTES
//
// The system uses the raw data found in the .ttf file without changing it
// and without building auxiliary data structures. This is a bit inefficient
// on little-endian systems (the data is big-endian), but assuming you're
// caching the bitmaps or glyph shapes this shouldn't be a big deal.
//
// It appears to be very hard to programmatically determine what font a
// given file is in a general way. I provide an API for this, but I don't
// recommend it.
//
//
// SOURCE STATISTICS (based on v0.6c, 2050 LOC)
//
// Documentation & header file 520 LOC \___ 660 LOC documentation
// Sample code 140 LOC /
// Truetype parsing 620 LOC ---- 620 LOC TrueType
// Software rasterization 240 LOC \.
// Curve tessellation 120 LOC \__ 550 LOC Bitmap creation
// Bitmap management 100 LOC /
// Baked bitmap interface 70 LOC /
// Font name matching & access 150 LOC ---- 150
// C runtime library abstraction 60 LOC ---- 60
//
//
// PERFORMANCE MEASUREMENTS FOR 1.06:
//
// 32-bit 64-bit
// Previous release: 8.83 s 7.68 s
// Pool allocations: 7.72 s 6.34 s
// Inline sort : 6.54 s 5.65 s
// New rasterizer : 5.63 s 5.00 s
//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
////
//// SAMPLE PROGRAMS
////
//
// Incomplete text-in-3d-api example, which draws quads properly aligned to be lossless
//
#if 0
#define STB_TRUETYPE_IMPLEMENTATION // force following include to generate implementation
#include "stb_truetype.h"
unsigned char ttf_buffer[1<<20];
unsigned char temp_bitmap[512*512];
stbtt_bakedchar cdata[96]; // ASCII 32..126 is 95 glyphs
GLuint ftex;
void my_stbtt_initfont(void)
{
fread(ttf_buffer, 1, 1<<20, fopen("c:/windows/fonts/times.ttf", "rb"));
stbtt_BakeFontBitmap(ttf_buffer,0, 32.0, temp_bitmap,512,512, 32,96, cdata); // no guarantee this fits!
// can free ttf_buffer at this point
glGenTextures(1, &ftex);
glBindTexture(GL_TEXTURE_2D, ftex);
glTexImage2D(GL_TEXTURE_2D, 0, GL_ALPHA, 512,512, 0, GL_ALPHA, GL_UNSIGNED_BYTE, temp_bitmap);
// can free temp_bitmap at this point
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
}
void my_stbtt_print(float x, float y, char *text)
{
// assume orthographic projection with units = screen pixels, origin at top left
glEnable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, ftex);
glBegin(GL_QUADS);
while (*text) {
if (*text >= 32 && *text < 128) {
stbtt_aligned_quad q;
stbtt_GetBakedQuad(cdata, 512,512, *text-32, &x,&y,&q,1);//1=opengl & d3d10+,0=d3d9
glTexCoord2f(q.s0,q.t1); glVertex2f(q.x0,q.y0);
glTexCoord2f(q.s1,q.t1); glVertex2f(q.x1,q.y0);
glTexCoord2f(q.s1,q.t0); glVertex2f(q.x1,q.y1);
glTexCoord2f(q.s0,q.t0); glVertex2f(q.x0,q.y1);
}
++text;
}
glEnd();
}
#endif
//
//
//////////////////////////////////////////////////////////////////////////////
//
// Complete program (this compiles): get a single bitmap, print as ASCII art
//
#if 0
#include <stdio.h>
#define STB_TRUETYPE_IMPLEMENTATION // force following include to generate implementation
#include "stb_truetype.h"
char ttf_buffer[1<<25];
int main(int argc, char **argv)
{
stbtt_fontinfo font;
unsigned char *bitmap;
int w,h,i,j,c = (argc > 1 ? atoi(argv[1]) : 'a'), s = (argc > 2 ? atoi(argv[2]) : 20);
fread(ttf_buffer, 1, 1<<25, fopen(argc > 3 ? argv[3] : "c:/windows/fonts/arialbd.ttf", "rb"));
stbtt_InitFont(&font, ttf_buffer, stbtt_GetFontOffsetForIndex(ttf_buffer,0));
bitmap = stbtt_GetCodepointBitmap(&font, 0,stbtt_ScaleForPixelHeight(&font, s), c, &w, &h, 0,0);
for (j=0; j < h; ++j) {
for (i=0; i < w; ++i)
putchar(" .:ioVM@"[bitmap[j*w+i]>>5]);
putchar('\n');
}
return 0;
}
#endif
//
// Output:
//
// .ii.
// @@@@@@.
// V@Mio@@o
// :i. V@V
// :oM@@M
// :@@@MM@M
// @@o o@M
// :@@. M@M
// @@@o@@@@
// :M@@V:@@.
//
//////////////////////////////////////////////////////////////////////////////
//
// Complete program: print "Hello World!" banner, with bugs
//
#if 0
char buffer[24<<20];
unsigned char screen[20][79];
int main(int arg, char **argv)
{
stbtt_fontinfo font;
int i,j,ascent,baseline,ch=0;
float scale, xpos=2; // leave a little padding in case the character extends left
char *text = "Heljo World!"; // intentionally misspelled to show 'lj' brokenness
fread(buffer, 1, 1000000, fopen("c:/windows/fonts/arialbd.ttf", "rb"));
stbtt_InitFont(&font, buffer, 0);
scale = stbtt_ScaleForPixelHeight(&font, 15);
stbtt_GetFontVMetrics(&font, &ascent,0,0);
baseline = (int) (ascent*scale);
while (text[ch]) {
int advance,lsb,x0,y0,x1,y1;
float x_shift = xpos - (float) floor(xpos);
stbtt_GetCodepointHMetrics(&font, text[ch], &advance, &lsb);
stbtt_GetCodepointBitmapBoxSubpixel(&font, text[ch], scale,scale,x_shift,0, &x0,&y0,&x1,&y1);
stbtt_MakeCodepointBitmapSubpixel(&font, &screen[baseline + y0][(int) xpos + x0], x1-x0,y1-y0, 79, scale,scale,x_shift,0, text[ch]);
// note that this stomps the old data, so where character boxes overlap (e.g. 'lj') it's wrong
// because this API is really for baking character bitmaps into textures. if you want to render
// a sequence of characters, you really need to render each bitmap to a temp buffer, then
// "alpha blend" that into the working buffer
xpos += (advance * scale);
if (text[ch+1])
xpos += scale*stbtt_GetCodepointKernAdvance(&font, text[ch],text[ch+1]);
++ch;
}
for (j=0; j < 20; ++j) {
for (i=0; i < 78; ++i)
putchar(" .:ioVM@"[screen[j][i]>>5]);
putchar('\n');
}
return 0;
}
#endif
//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
////
//// INTEGRATION WITH YOUR CODEBASE
////
//// The following sections allow you to supply alternate definitions
//// of C library functions used by stb_truetype, e.g. if you don't
//// link with the C runtime library.
#ifdef STB_TRUETYPE_IMPLEMENTATION
// #define your own (u)stbtt_int8/16/32 before including to override this
#ifndef stbtt_uint8
typedef unsigned char stbtt_uint8;
typedef signed char stbtt_int8;
typedef unsigned short stbtt_uint16;
typedef signed short stbtt_int16;
typedef unsigned int stbtt_uint32;
typedef signed int stbtt_int32;
#endif
typedef char stbtt__check_size32[sizeof(stbtt_int32)==4 ? 1 : -1];
typedef char stbtt__check_size16[sizeof(stbtt_int16)==2 ? 1 : -1];
// e.g. #define your own STBTT_ifloor/STBTT_iceil() to avoid math.h
#ifndef STBTT_ifloor
#include <math.h>
#define STBTT_ifloor(x) ((int) floor(x))
#define STBTT_iceil(x) ((int) ceil(x))
#endif
#ifndef STBTT_sqrt
#include <math.h>
#define STBTT_sqrt(x) sqrt(x)
#define STBTT_pow(x,y) pow(x,y)
#endif
#ifndef STBTT_fmod
#include <math.h>
#define STBTT_fmod(x,y) fmod(x,y)
#endif
#ifndef STBTT_cos
#include <math.h>
#define STBTT_cos(x) cos(x)
#define STBTT_acos(x) acos(x)
#endif
#ifndef STBTT_fabs
#include <math.h>
#define STBTT_fabs(x) fabs(x)
#endif
// #define your own functions "STBTT_malloc" / "STBTT_free" to avoid malloc.h
#ifndef STBTT_malloc
#include <stdlib.h>
#define STBTT_malloc(x,u) ((void)(u),malloc(x))
#define STBTT_free(x,u) ((void)(u),free(x))
#endif
#ifndef STBTT_assert
#include <assert.h>
#define STBTT_assert(x) assert(x)
#endif
#ifndef STBTT_strlen
#include <string.h>
#define STBTT_strlen(x) strlen(x)
#endif
#ifndef STBTT_memcpy
#include <string.h>
#define STBTT_memcpy memcpy
#define STBTT_memset memset
#endif
#endif
///////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////
////
//// INTERFACE
////
////
#ifndef __STB_INCLUDE_STB_TRUETYPE_H__
#define __STB_INCLUDE_STB_TRUETYPE_H__
#ifdef STBTT_STATIC
#define STBTT_DEF static
#else
#define STBTT_DEF extern
#endif
#ifdef __cplusplus
extern "C" {
#endif
// private structure
typedef struct
{
unsigned char *data;
int cursor;
int size;
} stbtt__buf;
//////////////////////////////////////////////////////////////////////////////
//
// TEXTURE BAKING API
//
// If you use this API, you only have to call two functions ever.
//
typedef struct
{
unsigned short x0,y0,x1,y1; // coordinates of bbox in bitmap
float xoff,yoff,xadvance;
} stbtt_bakedchar;
STBTT_DEF int stbtt_BakeFontBitmap(const unsigned char *data, int offset, // font location (use offset=0 for plain .ttf)
float pixel_height, // height of font in pixels
unsigned char *pixels, int pw, int ph, // bitmap to be filled in
int first_char, int num_chars, // characters to bake
stbtt_bakedchar *chardata); // you allocate this, it's num_chars long
// if return is positive, the first unused row of the bitmap
// if return is negative, returns the negative of the number of characters that fit
// if return is 0, no characters fit and no rows were used
// This uses a very crappy packing.
typedef struct
{
float x0,y0,s0,t0; // top-left
float x1,y1,s1,t1; // bottom-right
} stbtt_aligned_quad;
STBTT_DEF void stbtt_GetBakedQuad(const stbtt_bakedchar *chardata, int pw, int ph, // same data as above
int char_index, // character to display
float *xpos, float *ypos, // pointers to current position in screen pixel space
stbtt_aligned_quad *q, // output: quad to draw
int opengl_fillrule); // true if opengl fill rule; false if DX9 or earlier
// Call GetBakedQuad with char_index = 'character - first_char', and it
// creates the quad you need to draw and advances the current position.
//
// The coordinate system used assumes y increases downwards.
//
// Characters will extend both above and below the current position;
// see discussion of "BASELINE" above.
//
// It's inefficient; you might want to c&p it and optimize it.
STBTT_DEF void stbtt_GetScaledFontVMetrics(const unsigned char *fontdata, int index, float size, float *ascent, float *descent, float *lineGap);
// Query the font vertical metrics without having to create a font first.
//////////////////////////////////////////////////////////////////////////////
//
// NEW TEXTURE BAKING API
//
// This provides options for packing multiple fonts into one atlas, not
// perfectly but better than nothing.
typedef struct
{
unsigned short x0,y0,x1,y1; // coordinates of bbox in bitmap
float xoff,yoff,xadvance;
float xoff2,yoff2;
} stbtt_packedchar;
typedef struct stbtt_pack_context stbtt_pack_context;
typedef struct stbtt_fontinfo stbtt_fontinfo;
#ifndef STB_RECT_PACK_VERSION
typedef struct stbrp_rect stbrp_rect;
#endif
STBTT_DEF int stbtt_PackBegin(stbtt_pack_context *spc, unsigned char *pixels, int width, int height, int stride_in_bytes, int padding, void *alloc_context);
// Initializes a packing context stored in the passed-in stbtt_pack_context.
// Future calls using this context will pack characters into the bitmap passed
// in here: a 1-channel bitmap that is width * height. stride_in_bytes is
// the distance from one row to the next (or 0 to mean they are packed tightly
// together). "padding" is the amount of padding to leave between each
// character (normally you want '1' for bitmaps you'll use as textures with
// bilinear filtering).
//
// Returns 0 on failure, 1 on success.
STBTT_DEF void stbtt_PackEnd (stbtt_pack_context *spc);
// Cleans up the packing context and frees all memory.
#define STBTT_POINT_SIZE(x) (-(x))
STBTT_DEF int stbtt_PackFontRange(stbtt_pack_context *spc, const unsigned char *fontdata, int font_index, float font_size,
int first_unicode_char_in_range, int num_chars_in_range, stbtt_packedchar *chardata_for_range);
// Creates character bitmaps from the font_index'th font found in fontdata (use
// font_index=0 if you don't know what that is). It creates num_chars_in_range
// bitmaps for characters with unicode values starting at first_unicode_char_in_range
// and increasing. Data for how to render them is stored in chardata_for_range;
// pass these to stbtt_GetPackedQuad to get back renderable quads.
//
// font_size is the full height of the character from ascender to descender,
// as computed by stbtt_ScaleForPixelHeight. To use a point size as computed
// by stbtt_ScaleForMappingEmToPixels, wrap the point size in STBTT_POINT_SIZE()
// and pass that result as 'font_size':
// ..., 20 , ... // font max minus min y is 20 pixels tall
// ..., STBTT_POINT_SIZE(20), ... // 'M' is 20 pixels tall
typedef struct
{
float font_size;
int first_unicode_codepoint_in_range; // if non-zero, then the chars are continuous, and this is the first codepoint
int *array_of_unicode_codepoints; // if non-zero, then this is an array of unicode codepoints
int num_chars;
stbtt_packedchar *chardata_for_range; // output
unsigned char h_oversample, v_oversample; // don't set these, they're used internally
} stbtt_pack_range;
STBTT_DEF int stbtt_PackFontRanges(stbtt_pack_context *spc, const unsigned char *fontdata, int font_index, stbtt_pack_range *ranges, int num_ranges);
// Creates character bitmaps from multiple ranges of characters stored in
// ranges. This will usually create a better-packed bitmap than multiple
// calls to stbtt_PackFontRange. Note that you can call this multiple
// times within a single PackBegin/PackEnd.
STBTT_DEF void stbtt_PackSetOversampling(stbtt_pack_context *spc, unsigned int h_oversample, unsigned int v_oversample);
// Oversampling a font increases the quality by allowing higher-quality subpixel
// positioning, and is especially valuable at smaller text sizes.
//
// This function sets the amount of oversampling for all following calls to
// stbtt_PackFontRange(s) or stbtt_PackFontRangesGatherRects for a given
// pack context. The default (no oversampling) is achieved by h_oversample=1
// and v_oversample=1. The total number of pixels required is
// h_oversample*v_oversample larger than the default; for example, 2x2
// oversampling requires 4x the storage of 1x1. For best results, render
// oversampled textures with bilinear filtering. Look at the readme in
// stb/tests/oversample for information about oversampled fonts
//
// To use with PackFontRangesGather etc., you must set it before calls
// call to PackFontRangesGatherRects.
STBTT_DEF void stbtt_PackSetSkipMissingCodepoints(stbtt_pack_context *spc, int skip);
// If skip != 0, this tells stb_truetype to skip any codepoints for which
// there is no corresponding glyph. If skip=0, which is the default, then
// codepoints without a glyph recived the font's "missing character" glyph,
// typically an empty box by convention.
STBTT_DEF void stbtt_GetPackedQuad(const stbtt_packedchar *chardata, int pw, int ph, // same data as above
int char_index, // character to display
float *xpos, float *ypos, // pointers to current position in screen pixel space
stbtt_aligned_quad *q, // output: quad to draw
int align_to_integer);
STBTT_DEF int stbtt_PackFontRangesGatherRects(stbtt_pack_context *spc, const stbtt_fontinfo *info, stbtt_pack_range *ranges, int num_ranges, stbrp_rect *rects);
STBTT_DEF void stbtt_PackFontRangesPackRects(stbtt_pack_context *spc, stbrp_rect *rects, int num_rects);
STBTT_DEF int stbtt_PackFontRangesRenderIntoRects(stbtt_pack_context *spc, const stbtt_fontinfo *info, stbtt_pack_range *ranges, int num_ranges, stbrp_rect *rects);
// Calling these functions in sequence is roughly equivalent to calling
// stbtt_PackFontRanges(). If you more control over the packing of multiple
// fonts, or if you want to pack custom data into a font texture, take a look
// at the source to of stbtt_PackFontRanges() and create a custom version
// using these functions, e.g. call GatherRects multiple times,
// building up a single array of rects, then call PackRects once,
// then call RenderIntoRects repeatedly. This may result in a
// better packing than calling PackFontRanges multiple times
// (or it may not).
// this is an opaque structure that you shouldn't mess with which holds
// all the context needed from PackBegin to PackEnd.
struct stbtt_pack_context {
void *user_allocator_context;
void *pack_info;
int width;
int height;
int stride_in_bytes;
int padding;
int skip_missing;
unsigned int h_oversample, v_oversample;
unsigned char *pixels;
void *nodes;
};
//////////////////////////////////////////////////////////////////////////////
//
// FONT LOADING
//
//
STBTT_DEF int stbtt_GetNumberOfFonts(const unsigned char *data);
// This function will determine the number of fonts in a font file. TrueType
// collection (.ttc) files may contain multiple fonts, while TrueType font
// (.ttf) files only contain one font. The number of fonts can be used for
// indexing with the previous function where the index is between zero and one
// less than the total fonts. If an error occurs, -1 is returned.
STBTT_DEF int stbtt_GetFontOffsetForIndex(const unsigned char *data, int index);
// Each .ttf/.ttc file may have more than one font. Each font has a sequential
// index number starting from 0. Call this function to get the font offset for
// a given index; it returns -1 if the index is out of range. A regular .ttf
// file will only define one font and it always be at offset 0, so it will
// return '0' for index 0, and -1 for all other indices.
// The following structure is defined publicly so you can declare one on
// the stack or as a global or etc, but you should treat it as opaque.
struct stbtt_fontinfo
{
void * userdata;
unsigned char * data; // pointer to .ttf file
int fontstart; // offset of start of font
int numGlyphs; // number of glyphs, needed for range checking
int loca,head,glyf,hhea,hmtx,kern,gpos; // table locations as offset from start of .ttf
int index_map; // a cmap mapping for our chosen character encoding
int indexToLocFormat; // format needed to map from glyph index to glyph
stbtt__buf cff; // cff font data
stbtt__buf charstrings; // the charstring index
stbtt__buf gsubrs; // global charstring subroutines index
stbtt__buf subrs; // private charstring subroutines index
stbtt__buf fontdicts; // array of font dicts
stbtt__buf fdselect; // map from glyph to fontdict
};
STBTT_DEF int stbtt_InitFont(stbtt_fontinfo *info, const unsigned char *data, int offset);
// Given an offset into the file that defines a font, this function builds
// the necessary cached info for the rest of the system. You must allocate
// the stbtt_fontinfo yourself, and stbtt_InitFont will fill it out. You don't
// need to do anything special to free it, because the contents are pure
// value data with no additional data structures. Returns 0 on failure.
//////////////////////////////////////////////////////////////////////////////
//
// CHARACTER TO GLYPH-INDEX CONVERSIOn
STBTT_DEF int stbtt_FindGlyphIndex(const stbtt_fontinfo *info, int unicode_codepoint);
// If you're going to perform multiple operations on the same character
// and you want a speed-up, call this function with the character you're
// going to process, then use glyph-based functions instead of the
// codepoint-based functions.
// Returns 0 if the character codepoint is not defined in the font.
//////////////////////////////////////////////////////////////////////////////
//
// CHARACTER PROPERTIES
//
STBTT_DEF float stbtt_ScaleForPixelHeight(const stbtt_fontinfo *info, float pixels);
// computes a scale factor to produce a font whose "height" is 'pixels' tall.
// Height is measured as the distance from the highest ascender to the lowest
// descender; in other words, it's equivalent to calling stbtt_GetFontVMetrics
// and computing:
// scale = pixels / (ascent - descent)
// so if you prefer to measure height by the ascent only, use a similar calculation.
STBTT_DEF float stbtt_ScaleForMappingEmToPixels(const stbtt_fontinfo *info, float pixels);
// computes a scale factor to produce a font whose EM size is mapped to
// 'pixels' tall. This is probably what traditional APIs compute, but
// I'm not positive.
STBTT_DEF void stbtt_GetFontVMetrics(const stbtt_fontinfo *info, int *ascent, int *descent, int *lineGap);
// ascent is the coordinate above the baseline the font extends; descent
// is the coordinate below the baseline the font extends (i.e. it is typically negative)
// lineGap is the spacing between one row's descent and the next row's ascent...
// so you should advance the vertical position by "*ascent - *descent + *lineGap"
// these are expressed in unscaled coordinates, so you must multiply by
// the scale factor for a given size
STBTT_DEF int stbtt_GetFontVMetricsOS2(const stbtt_fontinfo *info, int *typoAscent, int *typoDescent, int *typoLineGap);
// analogous to GetFontVMetrics, but returns the "typographic" values from the OS/2
// table (specific to MS/Windows TTF files).
//
// Returns 1 on success (table present), 0 on failure.
STBTT_DEF void stbtt_GetFontBoundingBox(const stbtt_fontinfo *info, int *x0, int *y0, int *x1, int *y1);
// the bounding box around all possible characters
STBTT_DEF void stbtt_GetCodepointHMetrics(const stbtt_fontinfo *info, int codepoint, int *advanceWidth, int *leftSideBearing);
// leftSideBearing is the offset from the current horizontal position to the left edge of the character
// advanceWidth is the offset from the current horizontal position to the next horizontal position
// these are expressed in unscaled coordinates
STBTT_DEF int stbtt_GetCodepointKernAdvance(const stbtt_fontinfo *info, int ch1, int ch2);
// an additional amount to add to the 'advance' value between ch1 and ch2
STBTT_DEF int stbtt_GetCodepointBox(const stbtt_fontinfo *info, int codepoint, int *x0, int *y0, int *x1, int *y1);
// Gets the bounding box of the visible part of the glyph, in unscaled coordinates
STBTT_DEF void stbtt_GetGlyphHMetrics(const stbtt_fontinfo *info, int glyph_index, int *advanceWidth, int *leftSideBearing);
STBTT_DEF int stbtt_GetGlyphKernAdvance(const stbtt_fontinfo *info, int glyph1, int glyph2);
STBTT_DEF int stbtt_GetGlyphBox(const stbtt_fontinfo *info, int glyph_index, int *x0, int *y0, int *x1, int *y1);
// as above, but takes one or more glyph indices for greater efficiency
//////////////////////////////////////////////////////////////////////////////
//
// GLYPH SHAPES (you probably don't need these, but they have to go before
// the bitmaps for C declaration-order reasons)
//
#ifndef STBTT_vmove // you can predefine these to use different values (but why?)
enum {
STBTT_vmove=1,
STBTT_vline,
STBTT_vcurve,
STBTT_vcubic
};
#endif
#ifndef stbtt_vertex // you can predefine this to use different values
// (we share this with other code at RAD)
#define stbtt_vertex_type short // can't use stbtt_int16 because that's not visible in the header file
typedef struct
{
stbtt_vertex_type x,y,cx,cy,cx1,cy1;
unsigned char type,padding;
} stbtt_vertex;
#endif
STBTT_DEF int stbtt_IsGlyphEmpty(const stbtt_fontinfo *info, int glyph_index);
// returns non-zero if nothing is drawn for this glyph
STBTT_DEF int stbtt_GetCodepointShape(const stbtt_fontinfo *info, int unicode_codepoint, stbtt_vertex **vertices);
STBTT_DEF int stbtt_GetGlyphShape(const stbtt_fontinfo *info, int glyph_index, stbtt_vertex **vertices);
// returns # of vertices and fills *vertices with the pointer to them
// these are expressed in "unscaled" coordinates
//
// The shape is a series of contours. Each one starts with
// a STBTT_moveto, then consists of a series of mixed
// STBTT_lineto and STBTT_curveto segments. A lineto
// draws a line from previous endpoint to its x,y; a curveto
// draws a quadratic bezier from previous endpoint to
// its x,y, using cx,cy as the bezier control point.
STBTT_DEF void stbtt_FreeShape(const stbtt_fontinfo *info, stbtt_vertex *vertices);
// frees the data allocated above
//////////////////////////////////////////////////////////////////////////////
//
// BITMAP RENDERING
//
STBTT_DEF void stbtt_FreeBitmap(unsigned char *bitmap, void *userdata);
// frees the bitmap allocated below
STBTT_DEF unsigned char *stbtt_GetCodepointBitmap(const stbtt_fontinfo *info, float scale_x, float scale_y, int codepoint, int *width, int *height, int *xoff, int *yoff);
// allocates a large-enough single-channel 8bpp bitmap and renders the
// specified character/glyph at the specified scale into it, with
// antialiasing. 0 is no coverage (transparent), 255 is fully covered (opaque).
// *width & *height are filled out with the width & height of the bitmap,
// which is stored left-to-right, top-to-bottom.
//
// xoff/yoff are the offset it pixel space from the glyph origin to the top-left of the bitmap
STBTT_DEF unsigned char *stbtt_GetCodepointBitmapSubpixel(const stbtt_fontinfo *info, float scale_x, float scale_y, float shift_x, float shift_y, int codepoint, int *width, int *height, int *xoff, int *yoff);
// the same as stbtt_GetCodepoitnBitmap, but you can specify a subpixel
// shift for the character
STBTT_DEF void stbtt_MakeCodepointBitmap(const stbtt_fontinfo *info, unsigned char *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, int codepoint);
// the same as stbtt_GetCodepointBitmap, but you pass in storage for the bitmap
// in the form of 'output', with row spacing of 'out_stride' bytes. the bitmap
// is clipped to out_w/out_h bytes. Call stbtt_GetCodepointBitmapBox to get the
// width and height and positioning info for it first.
STBTT_DEF void stbtt_MakeCodepointBitmapSubpixel(const stbtt_fontinfo *info, unsigned char *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, float shift_x, float shift_y, int codepoint);
// same as stbtt_MakeCodepointBitmap, but you can specify a subpixel
// shift for the character
STBTT_DEF void stbtt_MakeCodepointBitmapSubpixelPrefilter(const stbtt_fontinfo *info, unsigned char *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, float shift_x, float shift_y, int oversample_x, int oversample_y, float *sub_x, float *sub_y, int codepoint);
// same as stbtt_MakeCodepointBitmapSubpixel, but prefiltering
// is performed (see stbtt_PackSetOversampling)
STBTT_DEF void stbtt_GetCodepointBitmapBox(const stbtt_fontinfo *font, int codepoint, float scale_x, float scale_y, int *ix0, int *iy0, int *ix1, int *iy1);
// get the bbox of the bitmap centered around the glyph origin; so the
// bitmap width is ix1-ix0, height is iy1-iy0, and location to place
// the bitmap top left is (leftSideBearing*scale,iy0).
// (Note that the bitmap uses y-increases-down, but the shape uses
// y-increases-up, so CodepointBitmapBox and CodepointBox are inverted.)
STBTT_DEF void stbtt_GetCodepointBitmapBoxSubpixel(const stbtt_fontinfo *font, int codepoint, float scale_x, float scale_y, float shift_x, float shift_y, int *ix0, int *iy0, int *ix1, int *iy1);
// same as stbtt_GetCodepointBitmapBox, but you can specify a subpixel
// shift for the character
// the following functions are equivalent to the above functions, but operate
// on glyph indices instead of Unicode codepoints (for efficiency)
STBTT_DEF unsigned char *stbtt_GetGlyphBitmap(const stbtt_fontinfo *info, float scale_x, float scale_y, int glyph, int *width, int *height, int *xoff, int *yoff);
STBTT_DEF unsigned char *stbtt_GetGlyphBitmapSubpixel(const stbtt_fontinfo *info, float scale_x, float scale_y, float shift_x, float shift_y, int glyph, int *width, int *height, int *xoff, int *yoff);
STBTT_DEF void stbtt_MakeGlyphBitmap(const stbtt_fontinfo *info, unsigned char *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, int glyph);
STBTT_DEF void stbtt_MakeGlyphBitmapSubpixel(const stbtt_fontinfo *info, unsigned char *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, float shift_x, float shift_y, int glyph);
STBTT_DEF void stbtt_MakeGlyphBitmapSubpixelPrefilter(const stbtt_fontinfo *info, unsigned char *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, float shift_x, float shift_y, int oversample_x, int oversample_y, float *sub_x, float *sub_y, int glyph);
STBTT_DEF void stbtt_GetGlyphBitmapBox(const stbtt_fontinfo *font, int glyph, float scale_x, float scale_y, int *ix0, int *iy0, int *ix1, int *iy1);
STBTT_DEF void stbtt_GetGlyphBitmapBoxSubpixel(const stbtt_fontinfo *font, int glyph, float scale_x, float scale_y,float shift_x, float shift_y, int *ix0, int *iy0, int *ix1, int *iy1);
// @TODO: don't expose this structure
typedef struct
{
int w,h,stride;
unsigned char *pixels;
} stbtt__bitmap;
// rasterize a shape with quadratic beziers into a bitmap
STBTT_DEF void stbtt_Rasterize(stbtt__bitmap *result, // 1-channel bitmap to draw into
float flatness_in_pixels, // allowable error of curve in pixels
stbtt_vertex *vertices, // array of vertices defining shape
int num_verts, // number of vertices in above array
float scale_x, float scale_y, // scale applied to input vertices
float shift_x, float shift_y, // translation applied to input vertices
int x_off, int y_off, // another translation applied to input
int invert, // if non-zero, vertically flip shape
void *userdata); // context for to STBTT_MALLOC
//////////////////////////////////////////////////////////////////////////////
//
// Signed Distance Function (or Field) rendering
STBTT_DEF void stbtt_FreeSDF(unsigned char *bitmap, void *userdata);
// frees the SDF bitmap allocated below
STBTT_DEF unsigned char * stbtt_GetGlyphSDF(const stbtt_fontinfo *info, float scale, int glyph, int padding, unsigned char onedge_value, float pixel_dist_scale, int *width, int *height, int *xoff, int *yoff);
STBTT_DEF unsigned char * stbtt_GetCodepointSDF(const stbtt_fontinfo *info, float scale, int codepoint, int padding, unsigned char onedge_value, float pixel_dist_scale, int *width, int *height, int *xoff, int *yoff);
// These functions compute a discretized SDF field for a single character, suitable for storing
// in a single-channel texture, sampling with bilinear filtering, and testing against
// larger than some threshold to produce scalable fonts.
// info -- the font
// scale -- controls the size of the resulting SDF bitmap, same as it would be creating a regular bitmap
// glyph/codepoint -- the character to generate the SDF for
// padding -- extra "pixels" around the character which are filled with the distance to the character (not 0),
// which allows effects like bit outlines
// onedge_value -- value 0-255 to test the SDF against to reconstruct the character (i.e. the isocontour of the character)
// pixel_dist_scale -- what value the SDF should increase by when moving one SDF "pixel" away from the edge (on the 0..255 scale)
// if positive, > onedge_value is inside; if negative, < onedge_value is inside
// width,height -- output height & width of the SDF bitmap (including padding)
// xoff,yoff -- output origin of the character
// return value -- a 2D array of bytes 0..255, width*height in size
//
// pixel_dist_scale & onedge_value are a scale & bias that allows you to make
// optimal use of the limited 0..255 for your application, trading off precision
// and special effects. SDF values outside the range 0..255 are clamped to 0..255.
//
// Example:
// scale = stbtt_ScaleForPixelHeight(22)
// padding = 5
// onedge_value = 180
// pixel_dist_scale = 180/5.0 = 36.0
//
// This will create an SDF bitmap in which the character is about 22 pixels
// high but the whole bitmap is about 22+5+5=32 pixels high. To produce a filled
// shape, sample the SDF at each pixel and fill the pixel if the SDF value
// is greater than or equal to 180/255. (You'll actually want to antialias,
// which is beyond the scope of this example.) Additionally, you can compute
// offset outlines (e.g. to stroke the character border inside & outside,
// or only outside). For example, to fill outside the character up to 3 SDF
// pixels, you would compare against (180-36.0*3)/255 = 72/255. The above
// choice of variables maps a range from 5 pixels outside the shape to
// 2 pixels inside the shape to 0..255; this is intended primarily for apply
// outside effects only (the interior range is needed to allow proper
// antialiasing of the font at *smaller* sizes)
//
// The function computes the SDF analytically at each SDF pixel, not by e.g.
// building a higher-res bitmap and approximating it. In theory the quality
// should be as high as possible for an SDF of this size & representation, but
// unclear if this is true in practice (perhaps building a higher-res bitmap
// and computing from that can allow drop-out prevention).
//
// The algorithm has not been optimized at all, so expect it to be slow
// if computing lots of characters or very large sizes.
//////////////////////////////////////////////////////////////////////////////
//
// Finding the right font...
//
// You should really just solve this offline, keep your own tables
// of what font is what, and don't try to get it out of the .ttf file.
// That's because getting it out of the .ttf file is really hard, because
// the names in the file can appear in many possible encodings, in many
// possible languages, and e.g. if you need a case-insensitive comparison,
// the details of that depend on the encoding & language in a complex way
// (actually underspecified in truetype, but also gigantic).
//
// But you can use the provided functions in two possible ways:
// stbtt_FindMatchingFont() will use *case-sensitive* comparisons on
// unicode-encoded names to try to find the font you want;
// you can run this before calling stbtt_InitFont()
//
// stbtt_GetFontNameString() lets you get any of the various strings
// from the file yourself and do your own comparisons on them.