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Add correct glyphs bitmap location rects with AGG

This commit is contained in:
Francesco Abbate 2020-05-31 13:53:27 +02:00
parent 7c57b1d6ca
commit 4ec521dd37
2 changed files with 43 additions and 16 deletions
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10
src/font_renderer_alpha.h
View File

@ -46,13 +46,17 @@ public:
m_trans(m_curves, m_mtx)
{ }
bool get_font_vmetrics(int& ascender, int& descender) {
int get_face_height() const {
return m_feng.face_height();
}
bool get_font_vmetrics(double& ascender, double& descender) {
int face_height = m_feng.face_height();
if (face_height > 0) {
double current_height = m_feng.height();
m_feng.height(1.0);
ascender = m_feng.ascender() * face_height;
descender = m_feng.descender() * face_height;
ascender = m_feng.ascender();
descender = m_feng.descender();
m_feng.height(current_height);
return true;
}

49
tests/agg_font_render_test.cpp
View File

@ -10,6 +10,12 @@
typedef struct { uint8_t b, g, r, a; } RenColor;
typedef struct { int x, y, width, height; } RenRect;
// Mirrors stbtt_bakedchar.
struct GlyphBitmapInfo {
unsigned short x0, y0, x1, y1;
float xoff, yoff, xadvance;
};
struct RenImage {
RenColor *pixels;
int width, height;
@ -17,14 +23,14 @@ struct RenImage {
struct GlyphSetA {
RenImage *image;
// FIXME: add glyphs information for AGG implementation
// stbtt_bakedchar glyphs[256];
GlyphBitmapInfo glyphs[256];
};
struct RenFontA {
font_renderer_alpha *renderer;
float size;
int height;
float ascender, descender;
// For some reason the font's height used in renderer.c
// when calling BakeFontBitmap is 0.5 off from 'height'.
float height_bitmap;
@ -63,13 +69,20 @@ RenFontA* ren_load_font_agg(const char *filename, float size) {
font->renderer = new font_renderer_alpha(false, false);
font->renderer->load_font(filename);
int ascender, descender;
double ascender, descender;
font->renderer->get_font_vmetrics(ascender, descender);
fprintf(stderr, "Font metrics ascender: %d descender: %d\n", ascender, descender);
int face_height = font->renderer->get_face_height();
// Gives the font's ascender and descender like stbtt.
fprintf(stderr, "Font metrics ascender: %g descender: %g\n", ascender * face_height, descender * face_height);
float scale = font->renderer->scale_for_em_to_pixels(size);
font->height = (ascender - descender) * scale + 0.5;
font->height_bitmap = (ascender - descender) * scale;
font->height = (ascender - descender) * face_height * scale + 0.5;
font->height_bitmap = (ascender - descender) * face_height * scale;
font->descender = descender * font->height_bitmap;
font->ascender = ascender * font->height_bitmap;
fprintf(stderr, "Font's pixel ascender: %g descender: %g sum: %g\n", font->ascender, font->descender, font->ascender - font->descender);
fprintf(stderr, "Font height: %d\n", font->height);
@ -92,22 +105,32 @@ retry:
agg::rendering_buffer ren_buf((agg::int8u *) set->image->pixels, width, height, -width * pixel_size);
// FIXME: figure out how to precisely layout each glyph.
double x = 4, y = height - font->height * 3 / 2;
double x = 0, y = height;
int res = 0;
const agg::alpha8 text_color(0xff);
for (int i = 0; i < 256; i++) {
if (x + font->height * 3 / 2 > width) {
x = 4;
y -= font->height * 3 / 2;
if (x + font->height > width) {
x = 0;
y -= font->height;
}
if (y < 0) {
if (y - font->height < 0) {
res = -1;
break;
}
// FIXME: we are ignoring idx and with a char we cannot pass codepoint > 255.
char text[2] = {char(i % 256), 0};
// FIXME: using font->size below is wrong.
font->renderer->render_text(ren_buf, font->height_bitmap, text_color, x, y, text);
// FIXME: using font->height_bitmap below seems logically correct but
// the font size is bigger than what printed by BakeFontBitmap.
double x_next = x, y_next = y - font->height;
font->renderer->render_text(ren_buf, font->height_bitmap, text_color, x_next, y_next, text);
set->glyphs[i].x0 = x - 1;
set->glyphs[i].y0 = y - font->descender;
set->glyphs[i].x1 = x_next - 1;
set->glyphs[i].y1 = y + font->ascender;
set->glyphs[i].xoff = -1;
set->glyphs[i].yoff = -font->ascender;
set->glyphs[i].xadvance = x_next - x;
x = x_next;
}
/* retry with a larger image buffer if the buffer wasn't large enough */