walkero
/
lite-xl
1
0
Fork 0
Code Issues 7 Pull Requests Projects Releases 13 Wiki Activity

Add missing padding pixel to avoid artifacts 

Using subpixel positioning we need one empty pixel as the left of each glyph.
This commit is contained in:
Francesco Abbate 2021-03-04 16:54:55 +01:00
parent 294f3f14fb
commit e441beae83
1 changed files with 13 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
lib/font_renderer/font_renderer.cpp
View File

@ -233,13 +233,17 @@ FR_Bitmap *FR_Bake_Font_Bitmap(FR_Renderer *font_renderer, int font_height,
for (int i = 0; i < num_chars; i++) {
const agg::rect_i& gbounds = bounds[index[i]];
if (gbounds.x2 < gbounds.x1) continue;
if (x + gbounds.x2 + 1 >= pixels_width * subpixel_scale) {
// 1. It is very important to ensure that the x's increment below (1) and in
// (2), (3) and (4) are perfectly the same.
if (x + gbounds.x2 + 3 * subpixel_scale >= pixels_width * subpixel_scale) {
x = x_start;
y = y_bottom;
}
// 5. Ensure that y's increment below is exactly the same to the one used in (6)
const int glyph_y_bottom = y - 2 * pad_y - (gbounds.y2 - gbounds.y1);
y_bottom = (y_bottom > glyph_y_bottom ? glyph_y_bottom : y_bottom);
x = x + gbounds.x2 + 2 * subpixel_scale;
// 2. Ensure x's increment is aligned with (1)
x = x + gbounds.x2 + 3 * subpixel_scale;
}
const int pixels_height = -y_bottom + 1;
@ -262,13 +266,15 @@ FR_Bitmap *FR_Bake_Font_Bitmap(FR_Renderer *font_renderer, int font_height,
const agg::rect_i& gbounds = bounds[index[i]];
if (gbounds.x2 < gbounds.x1) continue;
if (x + gbounds.x2 + 1 >= pixels_width * subpixel_scale) {
// 3. Ensure x's increment is aligned with (1)
if (x + gbounds.x2 + 3 * subpixel_scale >= pixels_width * subpixel_scale) {
// No more space along x, begin writing the row below.
x = x_start;
y = y_bottom;
}
const int y_baseline = y - pad_y - gbounds.y2;
// 6. Ensure the y's increment below is aligned with the increment used in (5)
const int glyph_y_bottom = y - 2 * pad_y - (gbounds.y2 - gbounds.y1);
y_bottom = (y_bottom > glyph_y_bottom ? glyph_y_bottom : y_bottom);
@ -296,8 +302,10 @@ FR_Bitmap *FR_Bake_Font_Bitmap(FR_Renderer *font_renderer, int font_height,
}
glyph_trim_rect(ren_buf, glyph_info, subpixel_scale);
// When subpixel is activated we need one padding pixel on the left and on the right.
x = x + gbounds.x2 + 2 * subpixel_scale;
// When subpixel is activated we need one padding pixel on the left and on the right
// and one more because of subpixel positioning.
// 4. Ensure x's increment is aligned with (1)
x = x + gbounds.x2 + 3 * subpixel_scale;
}
delete [] index;
delete [] bounds;