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renderer: rewrite glyph cache (#1845) 

* renderer: rewrite glyph cache

This commit splits the current GlyphSet-based system into 2 caches,
CharMap and GlyphMap, which maps codepoints -> glyph IDs and glyph IDs -> glyphs respectively.
Each GlyphMap contains a number of GlyphAtlas mapped by their width,
and each GlyphAtlas has a list of surfaces with the same width.
Surfaces within the GlyphAtlas acts like a bump allocator, but is flexible
enough to allow older GlyphAtlas surfaces to be recycled.

GlyphMetric now contains atlas_idx and surface_idx, which points to the correct surface.
Since GlyphAtlas supports rudimentary packing & allocation, we no longer render whole
GlyphSets and this speeds up rendering in most cases.

Tab width is no longer set with the hacky "modify the GlyphMetric" hack.

* renderer: set natlas to 0 after freeing

* renderer: fix printf warning

* renderer: fix memory leak

* renderer: better whitespace rendering

* renderer: fix ubsan warning when casting ints

* renderer: fix tab handling

There's a bug with inconsistent tab widths caused by fontgroups.

* renderer: fix glyphs being loaded over and over

* renderer: add glyphmap size

* renderer: store per-surface offset_y and use it to find best-fitting surface

* renderer: fix MSVC compiler error

* renderer: remove return value from ren_font_glyph

* renderer: refactor xadvance calculation

* renderer: fix double free SDL_RWops if FT_Set_Pixel_Size fail

* renderer: always try .notdef before U+25A1

* renderer: disable ren_font_dump yet again

Accidentally commited this change.

* renderer: remove unused imports

* renderer: fix double free with FT_Open_Face

* renderer: return SDL_Surface in font_find_glyph_surface

* renderer: bring back metric flags for future extension

* renderer: refactor xadvance calculation into macro

* renderer: fix comment

* renderer: store GlyphMetric directly in the surface

* renderer: remove duplicated comment

* renderer: rename font_find_glyph_surface to font_allocate_glyph_surface

* renderer: refactor glyphmetric retrieval into an inline function

* renderer: do not render glyphs with bitmap set to null

This is a weird edge case, but at least it shouldn't crash

* renderer: refactor face metric code into its own function

* renderer: actually check if glyph fits in surface

* renderer: rudimentary support for non-scalable faces

At least it won't render nothing on the screen

* renderer: check for font_surface instead of metric directly

This is safe and shorter

* renderer: fix indentation

* renderer: rename GLYPH_PER_ATLAS to GLYPHS_PER_ATLAS

* renderer: rename all GLYPH_PER_ATLAS correctly

* renderer: make utf8_to_codepoint slightly more durable

* renderer: fix compiler unsigned cast warning
This commit is contained in:
Takase 2024-07-13 08:39:49 +08:00 committed by GitHub
parent 5a427a89b5
commit 27d95f63cb
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
1 changed files with 351 additions and 188 deletions
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539
src/renderer.c
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@ -9,29 +9,23 @@
#include FT_OUTLINE_H #include FT_OUTLINE_H
#include FT_SYSTEM_H #include FT_SYSTEM_H
#ifdef _WIN32
#include <windows.h>
#include "utfconv.h"
#endif
#include "renderer.h" #include "renderer.h"
#include "renwindow.h" #include "renwindow.h"
#define MAX_UNICODE 0x100000 // uncomment the line below for more debugging information through printf
#define GLYPHSET_SIZE 256 // #define RENDERER_DEBUG
#define MAX_LOADABLE_GLYPHSETS (MAX_UNICODE / GLYPHSET_SIZE)
#define SUBPIXEL_BITMAPS_CACHED 3
static RenWindow **window_list = NULL; static RenWindow **window_list = NULL;
static size_t window_count = 0; static size_t window_count = 0;
static FT_Library library;
// draw_rect_surface is used as a 1x1 surface to simplify ren_draw_rect with blending // draw_rect_surface is used as a 1x1 surface to simplify ren_draw_rect with blending
static SDL_Surface *draw_rect_surface; static SDL_Surface *draw_rect_surface = NULL;
static FT_Library library = NULL;
static void* check_alloc(void *ptr) { #define check_alloc(P) _check_alloc(P, __FILE__, __LINE__)
static void* _check_alloc(void *ptr, const char *const file, size_t ln) {
if (!ptr) { if (!ptr) {
fprintf(stderr, "Fatal error: memory allocation failed\n"); fprintf(stderr, "%s:%zu: memory allocation failed\n", file, ln);
exit(EXIT_FAILURE); exit(EXIT_FAILURE);
} }
return ptr; return ptr;
@ -39,30 +33,76 @@ static void* check_alloc(void *ptr) {
/************************* Fonts *************************/ /************************* Fonts *************************/
// approximate number of glyphs per atlas surface
#define GLYPHS_PER_ATLAS 256
// some padding to add to atlas surface to store more glyphs
#define FONT_HEIGHT_OVERFLOW_PX 6
#define FONT_WIDTH_OVERFLOW_PX 6
// maximum unicode codepoint supported (https://stackoverflow.com/a/52203901)
#define MAX_UNICODE 0x10FFFF
// number of rows and columns in the codepoint map
#define CHARMAP_ROW 128
#define CHARMAP_COL (MAX_UNICODE / CHARMAP_ROW)
// the maximum number of glyphs for OpenType
#define MAX_GLYPHS 65535
// number of rows and columns in the glyph map
#define GLYPHMAP_ROW 128
#define GLYPHMAP_COL (MAX_GLYPHS / GLYPHMAP_ROW)
// number of subpixel bitmaps
#define SUBPIXEL_BITMAPS_CACHED 3
typedef enum {
EGlyphNone = 0,
EGlyphLoaded = (1 << 0L),
EGlyphBitmap = (1 << 1L),
// currently no-op because blits are always assumed to be dual source
EGlyphDualSource = (1 << 2L),
} ERenGlyphFlags;
// metrics for a loaded glyph
typedef struct { typedef struct {
unsigned int x0, x1, y0, y1, loaded; unsigned short atlas_idx, surface_idx;
unsigned int x1, y0, y1, flags;
int bitmap_left, bitmap_top; int bitmap_left, bitmap_top;
float xadvance; float xadvance;
} GlyphMetric; } GlyphMetric;
// maps codepoints -> glyph IDs
typedef struct { typedef struct {
SDL_Surface* surface; unsigned int *rows[CHARMAP_ROW];
GlyphMetric metrics[GLYPHSET_SIZE]; } CharMap;
} GlyphSet;
// a bitmap atlas with a fixed width, each surface acting as a bump allocator
typedef struct {
SDL_Surface **surfaces;
unsigned int width, nsurface;
} GlyphAtlas;
// maps glyph IDs -> glyph metrics
typedef struct {
// accessed with metrics[bitmap_idx][glyph_id / nrow][glyph_id - (row * ncol)]
GlyphMetric *metrics[SUBPIXEL_BITMAPS_CACHED][GLYPHMAP_ROW];
// accessed with atlas[bitmap_idx][atlas_idx].surfaces[surface_idx]
GlyphAtlas *atlas[SUBPIXEL_BITMAPS_CACHED];
size_t natlas, bytesize;
} GlyphMap;
typedef struct RenFont { typedef struct RenFont {
FT_Face face; FT_Face face;
FT_StreamRec stream; CharMap charmap;
GlyphSet* sets[SUBPIXEL_BITMAPS_CACHED][MAX_LOADABLE_GLYPHSETS]; GlyphMap glyphs;
float size, space_advance, tab_advance;
#ifdef LITE_USE_SDL_RENDERER #ifdef LITE_USE_SDL_RENDERER
int scale; int scale;
#endif #endif
unsigned short max_height, baseline, height; float size, space_advance;
unsigned short max_height, baseline, height, tab_size;
unsigned short underline_thickness;
ERenFontAntialiasing antialiasing; ERenFontAntialiasing antialiasing;
ERenFontHinting hinting; ERenFontHinting hinting;
unsigned char style; unsigned char style;
unsigned short underline_thickness;
char path[]; char path[];
} RenFont; } RenFont;
@ -79,7 +119,7 @@ void update_font_scale(RenWindow *window_renderer, RenFont **fonts) {
} }
#endif #endif
static const char* utf8_to_codepoint(const char *p, unsigned *dst) { static const char* utf8_to_codepoint(const char *p, const char *endp, unsigned *dst) {
const unsigned char *up = (unsigned char*)p; const unsigned char *up = (unsigned char*)p;
unsigned res, n; unsigned res, n;
switch (*p & 0xf0) { switch (*p & 0xf0) {
@ -89,7 +129,7 @@ static const char* utf8_to_codepoint(const char *p, unsigned *dst) {
case 0xc0 : res = *up & 0x1f; n = 1; break; case 0xc0 : res = *up & 0x1f; n = 1; break;
default : res = *up; n = 0; break; default : res = *up; n = 0; break;
} }
while (n--) { while (up < (const unsigned char *)endp && n--) {
res = (res << 6) | (*(++up) & 0x3f); res = (res << 6) | (*(++up) & 0x3f);
} }
*dst = res; *dst = res;
@ -109,7 +149,7 @@ static int font_set_render_options(RenFont* font) {
if (font->antialiasing == FONT_ANTIALIASING_SUBPIXEL) { if (font->antialiasing == FONT_ANTIALIASING_SUBPIXEL) {
unsigned char weights[] = { 0x10, 0x40, 0x70, 0x40, 0x10 } ; unsigned char weights[] = { 0x10, 0x40, 0x70, 0x40, 0x10 } ;
switch (font->hinting) { switch (font->hinting) {
case FONT_HINTING_NONE: FT_Library_SetLcdFilter(library, FT_LCD_FILTER_NONE); break; case FONT_HINTING_NONE: FT_Library_SetLcdFilter(library, FT_LCD_FILTER_NONE); break;
case FONT_HINTING_SLIGHT: case FONT_HINTING_SLIGHT:
case FONT_HINTING_FULL: FT_Library_SetLcdFilterWeights(library, weights); break; case FONT_HINTING_FULL: FT_Library_SetLcdFilterWeights(library, weights); break;
} }
@ -137,97 +177,201 @@ static int font_set_style(FT_Outline* outline, int x_translation, unsigned char
return 0; return 0;
} }
static void font_load_glyphset(RenFont* font, int idx) { static unsigned int font_get_glyph_id(RenFont *font, unsigned int codepoint) {
unsigned int render_option = font_set_render_options(font), load_option = font_set_load_options(font); if (codepoint > MAX_UNICODE) return 0;
int bitmaps_cached = font->antialiasing == FONT_ANTIALIASING_SUBPIXEL ? SUBPIXEL_BITMAPS_CACHED : 1; size_t row = codepoint / CHARMAP_COL;
unsigned int byte_width = font->antialiasing == FONT_ANTIALIASING_SUBPIXEL ? 3 : 1; size_t col = codepoint - (row * CHARMAP_COL);
for (int j = 0, pen_x = 0; j < bitmaps_cached; ++j) { if (!font->charmap.rows[row]) font->charmap.rows[row] = check_alloc(calloc(sizeof(unsigned int), CHARMAP_COL));
GlyphSet* set = check_alloc(calloc(1, sizeof(GlyphSet))); if (font->charmap.rows[row][col] == 0) {
font->sets[j][idx] = set; unsigned int glyph_id = FT_Get_Char_Index(font->face, codepoint);
for (int i = 0; i < GLYPHSET_SIZE; ++i) { // use -1 as a sentinel value for "glyph not available", a bit risky, but OpenType
int glyph_index = FT_Get_Char_Index(font->face, i + idx * GLYPHSET_SIZE); // uses uint16 to store glyph IDs. In theory this cannot ever be reached
if (!glyph_index || FT_Load_Glyph(font->face, glyph_index, load_option | FT_LOAD_BITMAP_METRICS_ONLY) font->charmap.rows[row][col] = glyph_id ? glyph_id : (unsigned int) -1;
|| font_set_style(&font->face->glyph->outline, j * (64 / SUBPIXEL_BITMAPS_CACHED), font->style) || FT_Render_Glyph(font->face->glyph, render_option)) { }
continue; return font->charmap.rows[row][col] == (unsigned int) -1 ? 0 : font->charmap.rows[row][col];
} }
FT_GlyphSlot slot = font->face->glyph;
unsigned int glyph_width = slot->bitmap.width / byte_width; #define FONT_IS_SUBPIXEL(F) ((F)->antialiasing == FONT_ANTIALIASING_SUBPIXEL)
if (font->antialiasing == FONT_ANTIALIASING_NONE) #define FONT_BITMAP_COUNT(F) ((F)->antialiasing == FONT_ANTIALIASING_SUBPIXEL ? SUBPIXEL_BITMAPS_CACHED : 1)
glyph_width *= 8;
set->metrics[i] = (GlyphMetric){ pen_x, pen_x + glyph_width, 0, slot->bitmap.rows, true, slot->bitmap_left, slot->bitmap_top, (slot->advance.x + slot->lsb_delta - slot->rsb_delta) / 64.0f}; static SDL_Surface *font_allocate_glyph_surface(RenFont *font, FT_GlyphSlot slot, int bitmap_idx, GlyphMetric *metric) {
pen_x += glyph_width; // get an atlas with the correct width
font->max_height = slot->bitmap.rows > font->max_height ? slot->bitmap.rows : font->max_height; int atlas_idx = -1;
// In order to fix issues with monospacing; we need the unhinted xadvance; as FreeType doesn't correctly report the hinted advance for spaces on monospace fonts (like RobotoMono). See #843. for (int i = 0; i < font->glyphs.natlas; i++) {
if (!glyph_index || FT_Load_Glyph(font->face, glyph_index, (load_option | FT_LOAD_BITMAP_METRICS_ONLY | FT_LOAD_NO_HINTING) & ~FT_LOAD_FORCE_AUTOHINT) if (font->glyphs.atlas[bitmap_idx][i].width >= metric->x1) {
|| font_set_style(&font->face->glyph->outline, j * (64 / SUBPIXEL_BITMAPS_CACHED), font->style) || FT_Render_Glyph(font->face->glyph, render_option)) { atlas_idx = i;
continue; break;
}
slot = font->face->glyph;
set->metrics[i].xadvance = slot->advance.x / 64.0f;
} }
if (pen_x == 0) }
if (atlas_idx < 0) {
// create a new atlas with the correct width, for each subpixel bitmap
for (int i = 0; i < FONT_BITMAP_COUNT(font); i++) {
font->glyphs.atlas[i] = check_alloc(realloc(font->glyphs.atlas[i], sizeof(GlyphAtlas) * (font->glyphs.natlas + 1)));
font->glyphs.atlas[i][font->glyphs.natlas] = (GlyphAtlas) {
.width = metric->x1 + FONT_WIDTH_OVERFLOW_PX, .nsurface = 0,
.surfaces = NULL,
};
}
font->glyphs.bytesize += sizeof(GlyphAtlas);
atlas_idx = font->glyphs.natlas++;
}
metric->atlas_idx = atlas_idx;
GlyphAtlas *atlas = &font->glyphs.atlas[bitmap_idx][atlas_idx];
// find the surface with the minimum height that can fit the glyph (limited to last 100 surfaces)
int surface_idx = -1, max_surface_idx = (int) atlas->nsurface - 100, min_waste = INT_MAX;
for (int i = atlas->nsurface - 1; i >= 0 && i > max_surface_idx; i--) {
assert(atlas->surfaces[i]->userdata);
GlyphMetric *m = (GlyphMetric *) atlas->surfaces[i]->userdata;
int new_min_waste = (int) atlas->surfaces[i]->h - (int) m->y1;
if (new_min_waste >= metric->y1 && new_min_waste < min_waste) {
surface_idx = i;
min_waste = new_min_waste;
}
}
if (surface_idx < 0) {
// allocate a new surface array, and a surface
int h = FONT_HEIGHT_OVERFLOW_PX + (double) font->face->size->metrics.height / 64.0f;
if (h <= FONT_HEIGHT_OVERFLOW_PX) h += slot->bitmap.rows;
if (h <= FONT_HEIGHT_OVERFLOW_PX) h += font->size;
atlas->surfaces = check_alloc(realloc(atlas->surfaces, sizeof(SDL_Surface *) * (atlas->nsurface + 1)));
atlas->surfaces[atlas->nsurface] = check_alloc(SDL_CreateRGBSurface(
0, atlas->width, GLYPHS_PER_ATLAS * h, FONT_BITMAP_COUNT(font) * 8,
0, 0, 0, 0
));
atlas->surfaces[atlas->nsurface]->userdata = NULL;
surface_idx = atlas->nsurface++;
font->glyphs.bytesize += (sizeof(SDL_Surface *) + sizeof(SDL_Surface) + atlas->width * GLYPHS_PER_ATLAS * h * FONT_BITMAP_COUNT(font));
}
metric->surface_idx = surface_idx;
if (atlas->surfaces[surface_idx]->userdata) {
GlyphMetric *last_metric = (GlyphMetric *) atlas->surfaces[surface_idx]->userdata;
metric->y0 = last_metric->y1; metric->y1 += last_metric->y1;
}
atlas->surfaces[surface_idx]->userdata = (void *) metric;
return atlas->surfaces[surface_idx];
}
static void font_load_glyph(RenFont *font, unsigned int glyph_id) {
unsigned int render_option = font_set_render_options(font);
unsigned int load_option = font_set_load_options(font);
// load the font without hinting to fix an issue with monospaced fonts,
// because freetype doesn't report the correct LSB and RSB delta. Transformation & subpixel positioning don't affect
// the xadvance, so we can save some time by not doing this step multiple times
if (FT_Load_Glyph(font->face, glyph_id, (load_option | FT_LOAD_BITMAP_METRICS_ONLY | FT_LOAD_NO_HINTING) & ~FT_LOAD_FORCE_AUTOHINT) != 0)
return;
double unhinted_xadv = font->face->glyph->advance.x / 64.0f;
// render the glyph for all bitmap
int bitmaps = FONT_BITMAP_COUNT(font);
int row = glyph_id / GLYPHMAP_COL, col = glyph_id - (row * GLYPHMAP_COL);
for (int bitmap_idx = 0; bitmap_idx < bitmaps; bitmap_idx++) {
FT_GlyphSlot slot = font->face->glyph;
if (FT_Load_Glyph(font->face, glyph_id, load_option | FT_LOAD_BITMAP_METRICS_ONLY) != 0
|| font_set_style(&slot->outline, bitmap_idx * (64 / SUBPIXEL_BITMAPS_CACHED), font->style) != 0
|| FT_Render_Glyph(slot, render_option) != 0)
return;
// save the metrics
if (!font->glyphs.metrics[bitmap_idx][row]) {
font->glyphs.metrics[bitmap_idx][row] = check_alloc(calloc(sizeof(GlyphMetric), GLYPHMAP_COL));
font->glyphs.bytesize += sizeof(GlyphMetric) * GLYPHMAP_COL;
}
GlyphMetric *metric = &font->glyphs.metrics[bitmap_idx][row][col];
metric->flags = EGlyphLoaded;
metric->xadvance = unhinted_xadv;
// if this bitmap is empty, or has a format we don't support, just store the xadvance
if (!slot->bitmap.width || !slot->bitmap.rows || !slot->bitmap.buffer ||
(slot->bitmap.pixel_mode != FT_PIXEL_MODE_MONO
&& slot->bitmap.pixel_mode != FT_PIXEL_MODE_GRAY
&& slot->bitmap.pixel_mode != FT_PIXEL_MODE_LCD))
continue; continue;
set->surface = check_alloc(SDL_CreateRGBSurface(0, pen_x, font->max_height, font->antialiasing == FONT_ANTIALIASING_SUBPIXEL ? 24 : 8, 0, 0, 0, 0));
uint8_t* pixels = set->surface->pixels; unsigned int glyph_width = slot->bitmap.width / bitmaps;
for (int i = 0; i < GLYPHSET_SIZE; ++i) { // FT_PIXEL_MODE_MONO uses 1 bit per pixel packed bitmap
int glyph_index = FT_Get_Char_Index(font->face, i + idx * GLYPHSET_SIZE); if (slot->bitmap.pixel_mode == FT_PIXEL_MODE_MONO) glyph_width *= 8;
if (!glyph_index || FT_Load_Glyph(font->face, glyph_index, load_option))
continue; metric->x1 = glyph_width;
FT_GlyphSlot slot = font->face->glyph; metric->y1 = slot->bitmap.rows;
font_set_style(&slot->outline, (64 / bitmaps_cached) * j, font->style); metric->bitmap_left = slot->bitmap_left;
if (FT_Render_Glyph(slot, render_option)) metric->bitmap_top = slot->bitmap_top;
continue; metric->flags |= (EGlyphBitmap | EGlyphDualSource);
for (unsigned int line = 0; line < slot->bitmap.rows; ++line) {
int target_offset = set->surface->pitch * line + set->metrics[i].x0 * byte_width; // find the best surface to copy the glyph over, and copy it
int source_offset = line * slot->bitmap.pitch; SDL_Surface *surface = font_allocate_glyph_surface(font, slot, bitmap_idx, metric);
if (font->antialiasing == FONT_ANTIALIASING_NONE) { uint8_t* pixels = surface->pixels;
for (unsigned int column = 0; column < slot->bitmap.width; ++column) { for (unsigned int line = 0; line < slot->bitmap.rows; ++line) {
int current_source_offset = source_offset + (column / 8); int target_offset = surface->pitch * (line + metric->y0); // x0 is always assumed to be 0
int source_pixel = slot->bitmap.buffer[current_source_offset]; int source_offset = line * slot->bitmap.pitch;
pixels[++target_offset] = ((source_pixel >> (7 - (column % 8))) & 0x1) * 0xFF; if (font->antialiasing == FONT_ANTIALIASING_NONE) {
} for (unsigned int column = 0; column < slot->bitmap.width; ++column) {
} else int current_source_offset = source_offset + (column / 8);
memcpy(&pixels[target_offset], &slot->bitmap.buffer[source_offset], slot->bitmap.width); int source_pixel = slot->bitmap.buffer[current_source_offset];
pixels[++target_offset] = ((source_pixel >> (7 - (column % 8))) & 0x1) * 0xFF;
}
} else {
memcpy(&pixels[target_offset], &slot->bitmap.buffer[source_offset], slot->bitmap.width);
} }
} }
} }
} }
static GlyphSet* font_get_glyphset(RenFont* font, unsigned int codepoint, int subpixel_idx) { // https://en.wikipedia.org/wiki/Whitespace_character
int idx = (codepoint / GLYPHSET_SIZE) % MAX_LOADABLE_GLYPHSETS; static inline int is_whitespace(unsigned int codepoint) {
if (!font->sets[font->antialiasing == FONT_ANTIALIASING_SUBPIXEL ? subpixel_idx : 0][idx]) switch (codepoint) {
font_load_glyphset(font, idx); case 0x20: case 0x85: case 0xA0: case 0x1680: case 0x2028: case 0x2029: case 0x202F: case 0x205F: case 0x3000: return 1;
return font->sets[font->antialiasing == FONT_ANTIALIASING_SUBPIXEL ? subpixel_idx : 0][idx]; }
return (codepoint >= 0x9 && codepoint <= 0xD) || (codepoint >= 0x2000 && codepoint <= 0x200A);
} }
static RenFont* font_group_get_glyph(GlyphSet** set, GlyphMetric** metric, RenFont** fonts, unsigned int codepoint, int bitmap_index) { static inline GlyphMetric *font_get_glyph(RenFont *font, unsigned int glyph_id, int subpixel_idx) {
if (!metric) { int row = glyph_id / GLYPHMAP_COL, col = glyph_id - (row * GLYPHMAP_COL);
return NULL; return font->glyphs.metrics[subpixel_idx][row] ? &font->glyphs.metrics[subpixel_idx][row][col] : NULL;
}
static RenFont *font_group_get_glyph(RenFont **fonts, unsigned int codepoint, int subpixel_idx, SDL_Surface **surface, GlyphMetric **metric) {
if (subpixel_idx < 0) subpixel_idx += SUBPIXEL_BITMAPS_CACHED;
RenFont *font = NULL;
unsigned int glyph_id = 0;
for (int i = 0; i < FONT_FALLBACK_MAX && fonts[i]; i++) {
font = fonts[i]; glyph_id = font_get_glyph_id(fonts[i], codepoint);
// use the first font that has representation for the glyph ID, but for whitespaces always use the first font
if (glyph_id || is_whitespace(codepoint)) break;
} }
if (bitmap_index < 0) // load the glyph if it is not loaded
bitmap_index += SUBPIXEL_BITMAPS_CACHED; subpixel_idx = FONT_IS_SUBPIXEL(font) ? subpixel_idx : 0;
for (int i = 0; i < FONT_FALLBACK_MAX && fonts[i]; ++i) { GlyphMetric *m = font_get_glyph(font, glyph_id, subpixel_idx);
*set = font_get_glyphset(fonts[i], codepoint, bitmap_index); if (!m || !(m->flags & EGlyphLoaded)) font_load_glyph(font, glyph_id);
*metric = &(*set)->metrics[codepoint % GLYPHSET_SIZE]; // if the glyph ID (possibly 0) is not available and we are not trying to load whitespace, try to load U+25A1 (box character)
if ((*metric)->loaded || codepoint < 0xFF) if ((!m || !(m->flags & EGlyphLoaded)) && codepoint != 0x25A1 && !is_whitespace(codepoint))
return fonts[i]; return font_group_get_glyph(fonts, 0x25A1, subpixel_idx, surface, metric);
} // fetch the glyph metrics again and save it
if (*metric && !(*metric)->loaded && codepoint > 0xFF && codepoint != 0x25A1) m = font_get_glyph(font, glyph_id, subpixel_idx);
return font_group_get_glyph(set, metric, fonts, 0x25A1, bitmap_index); if (metric && m) *metric = m;
return fonts[0]; if (surface && m && m->flags & EGlyphBitmap) *surface = font->glyphs.atlas[subpixel_idx][m->atlas_idx].surfaces[m->surface_idx];
return font;
} }
static void font_clear_glyph_cache(RenFont* font) { static void font_clear_glyph_cache(RenFont* font) {
for (int i = 0; i < SUBPIXEL_BITMAPS_CACHED; ++i) { int bitmaps = FONT_BITMAP_COUNT(font);
for (int j = 0; j < MAX_LOADABLE_GLYPHSETS; ++j) { for (int bitmap_idx = 0; bitmap_idx < bitmaps; bitmap_idx++) {
if (font->sets[i][j]) { for (int atlas_idx = 0; atlas_idx < font->glyphs.natlas; atlas_idx++) {
if (font->sets[i][j]->surface) GlyphAtlas *atlas = &font->glyphs.atlas[bitmap_idx][atlas_idx];
SDL_FreeSurface(font->sets[i][j]->surface); for (int surface_idx = 0; surface_idx < atlas->nsurface; surface_idx++) {
free(font->sets[i][j]); SDL_FreeSurface(atlas->surfaces[surface_idx]);
font->sets[i][j] = NULL;
} }
free(atlas->surfaces);
}
free(font->glyphs.atlas[bitmap_idx]);
font->glyphs.atlas[bitmap_idx] = NULL;
// clear glyph metric
for (int glyphmap_row = 0; glyphmap_row < GLYPHMAP_ROW; glyphmap_row++) {
free(font->glyphs.metrics[bitmap_idx][glyphmap_row]);
font->glyphs.metrics[bitmap_idx][glyphmap_row] = NULL;
} }
} }
font->glyphs.bytesize = 0;
font->glyphs.natlas = 0;
} }
// based on https://github.com/libsdl-org/SDL_ttf/blob/2a094959055fba09f7deed6e1ffeb986188982ae/SDL_ttf.c#L1735 // based on https://github.com/libsdl-org/SDL_ttf/blob/2a094959055fba09f7deed6e1ffeb986188982ae/SDL_ttf.c#L1735
@ -244,68 +388,74 @@ static unsigned long font_file_read(FT_Stream stream, unsigned long offset, unsi
} }
static void font_file_close(FT_Stream stream) { static void font_file_close(FT_Stream stream) {
if (stream && stream->descriptor.pointer) { if (stream && stream->descriptor.pointer)
SDL_RWclose((SDL_RWops *) stream->descriptor.pointer); SDL_RWclose((SDL_RWops *) stream->descriptor.pointer);
stream->descriptor.pointer = NULL; free(stream);
}
} }
RenFont* ren_font_load(const char* path, float size, ERenFontAntialiasing antialiasing, ERenFontHinting hinting, unsigned char style) { static int font_set_face_metrics(RenFont *font, FT_Face face) {
RenFont *font = NULL; FT_Error err;
FT_Face face = NULL; if ((err = FT_Set_Pixel_Sizes(face, 0, (int) font->size)) != 0)
return err;
SDL_RWops *file = SDL_RWFromFile(path, "rb");
if (!file)
goto rwops_failure;
int len = strlen(path);
font = check_alloc(calloc(1, sizeof(RenFont) + len + 1));
font->stream.read = font_file_read;
font->stream.close = font_file_close;
font->stream.descriptor.pointer = file;
font->stream.pos = 0;
font->stream.size = (unsigned long) SDL_RWsize(file);
if (FT_Open_Face(library, &(FT_Open_Args){ .flags = FT_OPEN_STREAM, .stream = &font->stream }, 0, &face))
goto failure;
if (FT_Set_Pixel_Sizes(face, 0, (int)(size)))
goto failure;
strcpy(font->path, path);
font->face = face; font->face = face;
font->size = size; if(FT_IS_SCALABLE(face)) {
#ifdef LITE_USE_SDL_RENDERER
font->scale = 1;
#endif
font->height = (short)((face->height / (float)face->units_per_EM) * font->size); font->height = (short)((face->height / (float)face->units_per_EM) * font->size);
font->baseline = (short)((face->ascender / (float)face->units_per_EM) * font->size); font->baseline = (short)((face->ascender / (float)face->units_per_EM) * font->size);
font->antialiasing = antialiasing;
font->hinting = hinting;
font->style = style;
if(FT_IS_SCALABLE(face)) if(FT_IS_SCALABLE(face))
font->underline_thickness = (unsigned short)((face->underline_thickness / (float)face->units_per_EM) * font->size); font->underline_thickness = (unsigned short)((face->underline_thickness / (float)face->units_per_EM) * font->size);
} else {
font->height = (short) font->face->size->metrics.height / 64.0f;
font->baseline = (short) font->face->size->metrics.ascender / 64.0f;
}
if(!font->underline_thickness) if(!font->underline_thickness)
font->underline_thickness = ceil((double) font->height / 14.0); font->underline_thickness = ceil((double) font->height / 14.0);
if (FT_Load_Char(face, ' ', font_set_load_options(font))) if ((err = FT_Load_Char(face, ' ', (font_set_load_options(font) | FT_LOAD_BITMAP_METRICS_ONLY | FT_LOAD_NO_HINTING) & ~FT_LOAD_FORCE_AUTOHINT)) != 0)
goto failure; return err;
font->space_advance = face->glyph->advance.x / 64.0f; font->space_advance = face->glyph->advance.x / 64.0f;
font->tab_advance = font->space_advance * 2; return 0;
}
RenFont* ren_font_load(const char* path, float size, ERenFontAntialiasing antialiasing, ERenFontHinting hinting, unsigned char style) {
SDL_RWops *file = NULL; RenFont *font = NULL;
FT_Face face = NULL; FT_Stream stream = NULL;
file = SDL_RWFromFile(path, "rb");
if (!file) return NULL;
int len = strlen(path);
font = check_alloc(calloc(1, sizeof(RenFont) + len + 1));
strcpy(font->path, path);
font->size = size;
font->antialiasing = antialiasing;
font->hinting = hinting;
font->style = style;
font->tab_size = 2;
#ifdef LITE_USE_SDL_RENDERER
font->scale = 1;
#endif
stream = check_alloc(calloc(1, sizeof(FT_StreamRec)));
if (!stream) goto stream_failure;
stream->read = &font_file_read;
stream->close = &font_file_close;
stream->descriptor.pointer = file;
stream->pos = 0;
stream->size = (unsigned long) SDL_RWsize(file);
if (FT_Open_Face(library, &(FT_Open_Args) { .flags = FT_OPEN_STREAM, .stream = stream }, 0, &face) != 0)
goto failure;
if (font_set_face_metrics(font, face) != 0)
goto failure;
return font; return font;
stream_failure:
if (file) SDL_RWclose(file);
failure: failure:
if (face) if (face) FT_Done_Face(face);
FT_Done_Face(face); if (font) free(font);
if (font)
free(font);
return NULL;
rwops_failure:
if (file)
SDL_RWclose(file);
return NULL; return NULL;
} }
@ -323,25 +473,22 @@ const char* ren_font_get_path(RenFont *font) {
void ren_font_free(RenFont* font) { void ren_font_free(RenFont* font) {
font_clear_glyph_cache(font); font_clear_glyph_cache(font);
// free codepoint cache as well
for (int i = 0; i < CHARMAP_ROW; i++) {
free(font->charmap.rows[i]);
}
FT_Done_Face(font->face); FT_Done_Face(font->face);
free(font); free(font);
} }
void ren_font_group_set_tab_size(RenFont **fonts, int n) { void ren_font_group_set_tab_size(RenFont **fonts, int n) {
unsigned int tab_index = '\t' % GLYPHSET_SIZE;
for (int j = 0; j < FONT_FALLBACK_MAX && fonts[j]; ++j) { for (int j = 0; j < FONT_FALLBACK_MAX && fonts[j]; ++j) {
for (int i = 0; i < (fonts[j]->antialiasing == FONT_ANTIALIASING_SUBPIXEL ? SUBPIXEL_BITMAPS_CACHED : 1); ++i) fonts[j]->tab_size = n;
font_get_glyphset(fonts[j], '\t', i)->metrics[tab_index].xadvance = fonts[j]->space_advance * n;
} }
} }
int ren_font_group_get_tab_size(RenFont **fonts) { int ren_font_group_get_tab_size(RenFont **fonts) {
unsigned int tab_index = '\t' % GLYPHSET_SIZE; return fonts[0]->tab_size;
float advance = font_get_glyphset(fonts[0], '\t', 0)->metrics[tab_index].xadvance;
if (fonts[0]->space_advance) {
advance /= fonts[0]->space_advance;
}
return advance;
} }
float ren_font_group_get_size(RenFont **fonts) { float ren_font_group_get_size(RenFont **fonts) {
@ -351,17 +498,12 @@ float ren_font_group_get_size(RenFont **fonts) {
void ren_font_group_set_size(RenFont **fonts, float size, int surface_scale) { void ren_font_group_set_size(RenFont **fonts, float size, int surface_scale) {
for (int i = 0; i < FONT_FALLBACK_MAX && fonts[i]; ++i) { for (int i = 0; i < FONT_FALLBACK_MAX && fonts[i]; ++i) {
font_clear_glyph_cache(fonts[i]); font_clear_glyph_cache(fonts[i]);
FT_Face face = fonts[i]->face;
FT_Set_Pixel_Sizes(face, 0, (int)(size*surface_scale));
fonts[i]->size = size; fonts[i]->size = size;
#ifdef LITE_USE_SDL_RENDERER fonts[i]->tab_size = 2;
#ifdef LITE_USE_SDL_RENDERER
fonts[i]->scale = surface_scale; fonts[i]->scale = surface_scale;
#endif #endif
fonts[i]->height = (short)((face->height / (float)face->units_per_EM) * size); font_set_face_metrics(fonts[i], fonts[i]->face);
fonts[i]->baseline = (short)((face->ascender / (float)face->units_per_EM) * size);
FT_Load_Char(face, ' ', font_set_load_options(fonts[i]));
fonts[i]->space_advance = face->glyph->advance.x / 64.0f;
fonts[i]->tab_advance = fonts[i]->space_advance * 2;
} }
} }
@ -369,26 +511,29 @@ int ren_font_group_get_height(RenFont **fonts) {
return fonts[0]->height; return fonts[0]->height;
} }
// some fonts provide xadvance for whitespaces (e.g. Unifont), which we need to ignore
#define FONT_GET_XADVANCE(F, C, M) (is_whitespace((C)) || !(M) || !(M)->xadvance \
? (F)->space_advance * (float) ((C) == '\t' ? (F)->tab_size : 1) \
: (M)->xadvance)
double ren_font_group_get_width(RenFont **fonts, const char *text, size_t len, int *x_offset) { double ren_font_group_get_width(RenFont **fonts, const char *text, size_t len, int *x_offset) {
double width = 0; double width = 0;
const char* end = text + len; const char* end = text + len;
GlyphMetric* metric = NULL; GlyphSet* set = NULL;
bool set_x_offset = x_offset == NULL; bool set_x_offset = x_offset == NULL;
while (text < end) { while (text < end) {
unsigned int codepoint; unsigned int codepoint;
text = utf8_to_codepoint(text, &codepoint); text = utf8_to_codepoint(text, end, &codepoint);
RenFont* font = font_group_get_glyph(&set, &metric, fonts, codepoint, 0); GlyphMetric *metric = NULL;
if (!metric) font_group_get_glyph(fonts, codepoint, 0, NULL, &metric);
break; width += FONT_GET_XADVANCE(fonts[0], codepoint, metric);
width += (!font || metric->xadvance) ? metric->xadvance : fonts[0]->space_advance; if (!set_x_offset && metric) {
if (!set_x_offset) {
set_x_offset = true; set_x_offset = true;
*x_offset = metric->bitmap_left; // TODO: should this be scaled by the surface scale? *x_offset = metric->bitmap_left; // TODO: should this be scaled by the surface scale?
} }
} }
if (!set_x_offset) { if (!set_x_offset)
*x_offset = 0; *x_offset = 0;
}
#ifdef LITE_USE_SDL_RENDERER #ifdef LITE_USE_SDL_RENDERER
return width / fonts[0]->scale; return width / fonts[0]->scale;
#else #else
@ -396,6 +541,24 @@ double ren_font_group_get_width(RenFont **fonts, const char *text, size_t len, i
#endif #endif
} }
#ifdef RENDERER_DEBUG
// this function can be used to debug font atlases, it is not public
void ren_font_dump(RenFont *font) {
char filename[1024];
int bitmaps = FONT_BITMAP_COUNT(font);
for (int bitmap_idx = 0; bitmap_idx < bitmaps; bitmap_idx++) {
for (int atlas_idx = 0; atlas_idx < font->glyphs.natlas; atlas_idx++) {
GlyphAtlas *atlas = &font->glyphs.atlas[bitmap_idx][atlas_idx];
for (int surface_idx = 0; surface_idx < atlas->nsurface; surface_idx++) {
snprintf(filename, 1024, "%s-%d-%d-%d.bmp", font->face->family_name, bitmap_idx, atlas_idx, surface_idx);
SDL_SaveBMP(atlas->surfaces[surface_idx], filename);
}
}
}
fprintf(stderr, "%s: %zu bytes\n", font->face->family_name, font->glyphs.bytesize);
}
#endif
double ren_draw_text(RenSurface *rs, RenFont **fonts, const char *text, size_t len, float x, int y, RenColor color) { double ren_draw_text(RenSurface *rs, RenFont **fonts, const char *text, size_t len, float x, int y, RenColor color) {
SDL_Surface *surface = rs->surface; SDL_Surface *surface = rs->surface;
SDL_Rect clip; SDL_Rect clip;
@ -404,7 +567,6 @@ double ren_draw_text(RenSurface *rs, RenFont **fonts, const char *text, size_t l
const int surface_scale = rs->scale; const int surface_scale = rs->scale;
double pen_x = x * surface_scale; double pen_x = x * surface_scale;
y *= surface_scale; y *= surface_scale;
int bytes_per_pixel = surface->format->BytesPerPixel;
const char* end = text + len; const char* end = text + len;
uint8_t* destination_pixels = surface->pixels; uint8_t* destination_pixels = surface->pixels;
int clip_end_x = clip.x + clip.w, clip_end_y = clip.y + clip.h; int clip_end_x = clip.x + clip.w, clip_end_y = clip.y + clip.h;
@ -416,20 +578,20 @@ double ren_draw_text(RenSurface *rs, RenFont **fonts, const char *text, size_t l
while (text < end) { while (text < end) {
unsigned int codepoint, r, g, b; unsigned int codepoint, r, g, b;
text = utf8_to_codepoint(text, &codepoint); text = utf8_to_codepoint(text, end, &codepoint);
GlyphSet* set = NULL; GlyphMetric* metric = NULL; SDL_Surface *font_surface = NULL; GlyphMetric *metric = NULL;
RenFont* font = font_group_get_glyph(&set, &metric, fonts, codepoint, (int)(fmod(pen_x, 1.0) * SUBPIXEL_BITMAPS_CACHED)); RenFont* font = font_group_get_glyph(fonts, codepoint, (int)(fmod(pen_x, 1.0) * SUBPIXEL_BITMAPS_CACHED), &font_surface, &metric);
if (!metric) if (!metric)
break; break;
int start_x = floor(pen_x) + metric->bitmap_left; int start_x = floor(pen_x) + metric->bitmap_left;
int end_x = (metric->x1 - metric->x0) + start_x; int end_x = metric->x1 + start_x; // x0 is assumed to be 0
int glyph_end = metric->x1, glyph_start = metric->x0; int glyph_end = metric->x1, glyph_start = 0;
if (!metric->loaded && codepoint > 0xFF) if (!font_surface && !is_whitespace(codepoint))
ren_draw_rect(rs, (RenRect){ start_x + 1, y, font->space_advance - 1, ren_font_group_get_height(fonts) }, color); ren_draw_rect(rs, (RenRect){ start_x + 1, y, font->space_advance - 1, ren_font_group_get_height(fonts) }, color);
if (set->surface && color.a > 0 && end_x >= clip.x && start_x < clip_end_x) { if (!is_whitespace(codepoint) && font_surface && color.a > 0 && end_x >= clip.x && start_x < clip_end_x) {
uint8_t* source_pixels = set->surface->pixels; uint8_t* source_pixels = font_surface->pixels;
for (int line = metric->y0; line < metric->y1; ++line) { for (int line = metric->y0; line < metric->y1; ++line) {
int target_y = line + y - metric->bitmap_top + fonts[0]->baseline * surface_scale; int target_y = line - metric->y0 + y - metric->bitmap_top + (fonts[0]->baseline * surface_scale);
if (target_y < clip.y) if (target_y < clip.y)
continue; continue;
if (target_y >= clip_end_y) if (target_y >= clip_end_y)
@ -441,8 +603,8 @@ double ren_draw_text(RenSurface *rs, RenFont **fonts, const char *text, size_t l
start_x += offset; start_x += offset;
glyph_start += offset; glyph_start += offset;
} }
uint32_t* destination_pixel = (uint32_t*)&(destination_pixels[surface->pitch * target_y + start_x * bytes_per_pixel]); uint32_t* destination_pixel = (uint32_t*)&(destination_pixels[surface->pitch * target_y + start_x * surface->format->BytesPerPixel ]);
uint8_t* source_pixel = &source_pixels[line * set->surface->pitch + glyph_start * (font->antialiasing == FONT_ANTIALIASING_SUBPIXEL ? 3 : 1)]; uint8_t* source_pixel = &source_pixels[line * font_surface->pitch + glyph_start * font_surface->format->BytesPerPixel];
for (int x = glyph_start; x < glyph_end; ++x) { for (int x = glyph_start; x < glyph_end; ++x) {
uint32_t destination_color = *destination_pixel; uint32_t destination_color = *destination_pixel;
// the standard way of doing this would be SDL_GetRGBA, but that introduces a performance regression. needs to be investigated // the standard way of doing this would be SDL_GetRGBA, but that introduces a performance regression. needs to be investigated
@ -465,12 +627,12 @@ double ren_draw_text(RenSurface *rs, RenFont **fonts, const char *text, size_t l
g = (color.g * src.g * color.a + dst.g * (65025 - src.g * color.a) + 32767) / 65025; g = (color.g * src.g * color.a + dst.g * (65025 - src.g * color.a) + 32767) / 65025;
b = (color.b * src.b * color.a + dst.b * (65025 - src.b * color.a) + 32767) / 65025; b = (color.b * src.b * color.a + dst.b * (65025 - src.b * color.a) + 32767) / 65025;
// the standard way of doing this would be SDL_GetRGBA, but that introduces a performance regression. needs to be investigated // the standard way of doing this would be SDL_GetRGBA, but that introduces a performance regression. needs to be investigated
*destination_pixel++ = dst.a << surface->format->Ashift | r << surface->format->Rshift | g << surface->format->Gshift | b << surface->format->Bshift; *destination_pixel++ = (unsigned int) dst.a << surface->format->Ashift | r << surface->format->Rshift | g << surface->format->Gshift | b << surface->format->Bshift;
} }
} }
} }
float adv = metric->xadvance ? metric->xadvance : font->space_advance; float adv = FONT_GET_XADVANCE(fonts[0], codepoint, metric);
if(!last) last = font; if(!last) last = font;
else if(font != last || text == end) { else if(font != last || text == end) {
@ -547,14 +709,15 @@ int ren_init(void) {
draw_rect_surface = SDL_CreateRGBSurface(0, 1, 1, 32, draw_rect_surface = SDL_CreateRGBSurface(0, 1, 1, 32,
0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF); 0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF);
if ((err = FT_Init_FreeType( &library ))) if ((err = FT_Init_FreeType(&library)) != 0)
return err; return err;
return 0; return 0;
} }
void ren_free(void) { void ren_free(void) {
SDL_FreeSurface(draw_rect_surface); SDL_FreeSurface(draw_rect_surface);
FT_Done_FreeType(library);
} }
RenWindow* ren_create(SDL_Window *win) { RenWindow* ren_create(SDL_Window *win) {