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Move rendering buffers pointers computations inside FontRendererBlendGammaSubpixel 

The logic is to disentangle the code between renderer.c and FontRenderer
so that this latter has a simple, logical interface.
This commit is contained in:
Francesco Abbate 2020-06-11 16:39:11 +02:00
parent 18865fd32f
commit ce664f85b1
3 changed files with 82 additions and 74 deletions
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38
lib/font_renderer/font_renderer.cpp
View File

@ -277,6 +277,7 @@ void blend_solid_hspan_rgb_subpixel(agg::rendering_buffer& rbuf, agg::gamma_lut<
}
}
#if 0
// destination implicitly BGRA32. Source implictly single-byte renderer_alpha coverage.
void FontRendererBlendGamma(FontRenderer *font_renderer, uint8_t *dst, int dst_stride, uint8_t *src, int src_stride, int region_width, int region_height, FontRendererColor color) {
blender_gamma_type& blender = font_renderer->blender();
@ -287,16 +288,43 @@ void FontRendererBlendGamma(FontRenderer *font_renderer, uint8_t *dst, int dst_s
blend_solid_hspan(dst_ren_buf, blender, x, y, region_width, color_a, covers);
}
}
#endif
// destination implicitly BGRA32. Source implictly single-byte renderer_alpha coverage with subpixel scale = 3.
void FontRendererBlendGammaSubpixel(FontRenderer *font_renderer, uint8_t *dst, int dst_stride, uint8_t *src, int src_stride, int region_width, int region_height, FontRendererColor color) {
const int subpixel_scale = 3;
// FIXME: consider using something like RenColor* instead of uint8_t * for dst.
void FontRendererBlendGammaSubpixel(FontRenderer *font_renderer, FontRendererClipArea *clip, int x, int y, uint8_t *dst, int dst_width, const FontRendererBitmap *glyphs_bitmap, const GlyphBitmapInfo *glyph, FontRendererColor color) {
agg::gamma_lut<>& gamma = font_renderer->gamma();
agg::lcd_distribution_lut& lcd_lut = font_renderer->lcd_distribution_lut();
agg::rendering_buffer dst_ren_buf(dst, region_width, region_height, dst_stride);
const int subpixel_scale = 3;
const int pixel_size = 4; // Pixel size for BGRA32 format.
x += glyph->xoff;
y += glyph->yoff;
int glyph_x = glyph->x0, glyph_y = glyph->y0;
int glyph_width = glyph->x1 - glyph->x0;
int glyph_height = glyph->y1 - glyph->y0;
int n;
if ((n = clip->left - x) > 0) { glyph_width -= n; glyph_x += n; x += n; }
if ((n = clip->top - y) > 0) { glyph_height -= n; glyph_y += n; y += n; }
if ((n = x + glyph_width - clip->right ) > 0) { glyph_width -= n; }
if ((n = y + glyph_height - clip->bottom) > 0) { glyph_height -= n; }
if (glyph_width <= 0 || glyph_height <= 0) {
return;
}
dst += (x + y * dst_width) * pixel_size;
agg::rendering_buffer dst_ren_buf(dst, glyph_width, glyph_height, dst_width * pixel_size);
uint8_t *src = glyphs_bitmap->pixels + (glyph_x + glyph_y * glyphs_bitmap->width) * subpixel_scale;
int src_stride = glyphs_bitmap->width * subpixel_scale;
const agg::rgba8 color_a(color.r, color.g, color.b);
for (int x = 0, y = 0; y < region_height; y++) {
for (int x = 0, y = 0; y < glyph_height; y++) {
agg::int8u *covers = src + y * src_stride;
blend_solid_hspan_rgb_subpixel(dst_ren_buf, gamma, lcd_lut, x, y, region_width * subpixel_scale, color_a, covers);
blend_solid_hspan_rgb_subpixel(dst_ren_buf, gamma, lcd_lut, x, y, glyph_width * subpixel_scale, color_a, covers);
}
}

26
lib/font_renderer/font_renderer.h
View File

@ -7,12 +7,19 @@
extern "C" {
#endif
// Mirrors stbtt_bakedchar.
typedef struct {
unsigned short x0, y0, x1, y1;
float xoff, yoff, xadvance;
} GlyphBitmapInfo;
// Important: when a subpixel scale is used the width below will be the width in logical pixel.
// As each logical pixel contains 3 subpixels it means that the 'pixels' pointer
// will hold enough space for '3 * width' uint8_t values.
typedef struct {
uint8_t *pixels;
int width, height;
} FontRendererBitmap;
struct FontRendererImpl;
typedef struct FontRendererImpl FontRenderer;
@ -26,6 +33,10 @@ typedef struct {
uint8_t r, g, b;
} FontRendererColor;
typedef struct {
int left, top, right, bottom;
} FontRendererClipArea;
FontRenderer * FontRendererNew(unsigned int flags, float gamma);
void FontRendererFree(FontRenderer *);
@ -39,17 +50,20 @@ int FontRendererBakeFontBitmap(FontRenderer *, int font_height,
int first_char, int num_chars, GlyphBitmapInfo *glyph_info,
int subpixel_scale);
#if 0
// FIXME: this function needs to be updated to match BlendGammaSubpixel.
void FontRendererBlendGamma(FontRenderer *,
uint8_t *dst, int dst_stride,
uint8_t *src, int src_stride,
int region_width, int region_height,
FontRendererColor color);
#endif
void FontRendererBlendGammaSubpixel(FontRenderer *,
uint8_t *dst, int dst_stride,
uint8_t *src, int src_stride,
int region_width, int region_height,
FontRendererColor color);
void FontRendererBlendGammaSubpixel(FontRenderer *font_renderer,
FontRendererClipArea *clip, int x, int y,
uint8_t *dst, int dst_width,
const FontRendererBitmap *glyphs_bitmap,
const GlyphBitmapInfo *glyph, FontRendererColor color);
#ifdef __cplusplus
}

92
src/renderer.c
View File

@ -12,16 +12,8 @@ struct RenImage {
int width, height;
};
// Important: when a subpixel scale is used the width below will be the width in logical pixel.
// As each logical pixel contains 3 subpixels it means that the 'pixels' pointer
// will hold enough space for '3 * width' uint8_t values.
typedef struct {
uint8_t *pixels;
int width, height;
} RenCoverageImage;
struct GlyphSet {
RenCoverageImage *coverage;
FontRendererBitmap *image;
GlyphBitmapInfo glyphs[256];
};
typedef struct GlyphSet GlyphSet;
@ -36,8 +28,8 @@ struct RenFont {
static SDL_Window *window;
static struct { int left, top, right, bottom; } clip;
//static struct { int left, top, right, bottom; } clip;
static FontRendererClipArea clip;
static void* check_alloc(void *ptr) {
if (!ptr) {
@ -108,9 +100,14 @@ RenImage* ren_new_image(int width, int height) {
return image;
}
RenCoverageImage* ren_new_coverage(int width, int height, int subpixel_scale) {
void ren_free_image(RenImage *image) {
free(image);
}
// FIXME: move this function into FontRenderer and change name.
FontRendererBitmap* ren_new_coverage_image(int width, int height, int subpixel_scale) {
assert(width > 0 && height > 0);
RenCoverageImage *image = malloc(sizeof(RenCoverageImage) + width * height * subpixel_scale * sizeof(uint8_t));
FontRendererBitmap *image = malloc(sizeof(FontRendererBitmap) + width * height * subpixel_scale * sizeof(uint8_t));
check_alloc(image);
image->pixels = (void*) (image + 1);
image->width = width;
@ -118,14 +115,10 @@ RenCoverageImage* ren_new_coverage(int width, int height, int subpixel_scale) {
return image;
}
void ren_free_image(RenImage *image) {
void ren_free_coverage_image(FontRendererBitmap *image) {
free(image);
}
void ren_free_coverage(RenCoverageImage *coverage) {
free(coverage);
}
static GlyphSet* load_glyphset(RenFont *font, int idx) {
GlyphSet *set = check_alloc(calloc(1, sizeof(GlyphSet)));
@ -135,17 +128,17 @@ static GlyphSet* load_glyphset(RenFont *font, int idx) {
int width = 128;
int height = 128;
retry:
set->coverage = ren_new_coverage(width, height, subpixel_scale);
set->image = ren_new_coverage_image(width, height, subpixel_scale);
int res = FontRendererBakeFontBitmap(font->renderer, font->height,
(void *) set->coverage->pixels, width, height,
(void *) set->image->pixels, width, height,
idx << 8, 256, set->glyphs, subpixel_scale);
/* retry with a larger image buffer if the buffer wasn't large enough */
if (res < 0) {
width *= 2;
height *= 2;
ren_free_coverage(set->coverage);
ren_free_coverage_image(set->image);
goto retry;
}
@ -195,7 +188,7 @@ void ren_free_font(RenFont *font) {
for (int i = 0; i < MAX_GLYPHSET; i++) {
GlyphSet *set = font->sets[i];
if (set) {
ren_free_coverage(set->coverage);
ren_free_coverage_image(set->image);
free(set);
}
}
@ -279,19 +272,14 @@ void ren_draw_rect(RenRect rect, RenColor color) {
}
}
static void clip_point_inside_rect(int *x, int *y, RenRect *sub) {
/* clip */
int n;
if ((n = clip.left - (*x)) > 0) { sub->width -= n; sub->x += n; (*x) += n; }
if ((n = clip.top - (*y)) > 0) { sub->height -= n; sub->y += n; (*y) += n; }
if ((n = (*x) + sub->width - clip.right ) > 0) { sub->width -= n; }
if ((n = (*y) + sub->height - clip.bottom) > 0) { sub->height -= n; }
}
void ren_draw_image(RenImage *image, RenRect *sub, int x, int y, RenColor color) {
if (color.a == 0) { return; }
clip_point_inside_rect(&x, &y, sub);
int n;
if ((n = clip.left - x) > 0) { sub->width -= n; sub->x += n; x += n; }
if ((n = clip.top - y) > 0) { sub->height -= n; sub->y += n; x += n; }
if ((n = x + sub->width - clip.right ) > 0) { sub->width -= n; }
if ((n = y + sub->height - clip.bottom) > 0) { sub->height -= n; }
if (sub->width <= 0 || sub->height <= 0) {
return;
@ -317,44 +305,22 @@ void ren_draw_image(RenImage *image, RenRect *sub, int x, int y, RenColor color)
}
}
static void ren_draw_coverage_with_color(FontRenderer *renderer, RenCoverageImage *image, RenRect *sub, int x, int y, RenColor color) {
if (color.a == 0) { return; }
clip_point_inside_rect(&x, &y, sub);
if (sub->width <= 0 || sub->height <= 0) {
return;
}
/* draw */
SDL_Surface *surf = SDL_GetWindowSurface(window);
const int subpixel_scale = 3;
uint8_t *s = image->pixels;
RenColor *d = (RenColor*) surf->pixels;
s += (sub->x + sub->y * image->width) * subpixel_scale;
d += x + y * surf->w;
const int surf_pixel_size = 4;
FontRendererBlendGammaSubpixel(
renderer,
(uint8_t *) d, surf->w * surf_pixel_size,
s, image->width * subpixel_scale,
sub->width, sub->height,
(FontRendererColor) { .r = color.r, .g = color.g, .b = color.b });
}
int ren_draw_text(RenFont *font, const char *text, int x, int y, RenColor color) {
RenRect rect;
const char *p = text;
unsigned codepoint;
SDL_Surface *surf = SDL_GetWindowSurface(window);
FontRendererColor color_fr = { .r = color.r, .g = color.g, .b = color.b };
while (*p) {
p = utf8_to_codepoint(p, &codepoint);
GlyphSet *set = get_glyphset(font, codepoint);
GlyphBitmapInfo *g = &set->glyphs[codepoint & 0xff];
rect.x = g->x0;
rect.y = g->y0;
rect.width = g->x1 - g->x0;
rect.height = g->y1 - g->y0;
ren_draw_coverage_with_color(font->renderer, set->coverage, &rect, x + g->xoff, y + g->yoff, color);
if (color.a != 0) {
FontRendererBlendGammaSubpixel(
font->renderer, &clip,
x, y,
(uint8_t *) surf->pixels, surf->w,
set->image, g, color_fr);
}
x += g->xadvance;
}
return x;