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Improve anti aliased text rendering #25

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alexfaria wants to merge 6 commits into from
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Improve anti aliased text rendering #25

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2322d42
Fix trailing ghost vertical edge on right edge of character on antial…
alexfaria Feb 24, 2026
642f2b0
Invert the gray colours for anti-aliased text if the background is black
alexfaria Feb 24, 2026
4c34412
Clear line buffer before decoding in antialiasing
alexfaria Feb 24, 2026
efab00c
Skip background pixels when rendering AA fonts
alexfaria Feb 25, 2026
2789112
Remove unnecessary memset
alexfaria Apr 14, 2026
de8face
Fix antialiased text palette lookup latency
alexfaria Apr 14, 2026
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13 changes: 11 additions & 2 deletions src/bb_ep_gfx.inl
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Original file line number Diff line number Diff line change
Expand Up @@ -1141,20 +1141,29 @@ int bbepWriteStringCustom(FASTEPDSTATE *pBBEP, const void *pFont, int x, int y,
}
tw = w;
if (pBBEP->anti_alias) { // draw half-size anti-aliased characters
const uint8_t grayColors[4] = {0xf, 0xc, 0x6, 0};
const uint8_t grayColorPalette[4] = {0xf, 0xc, 0x6, 0};
const uint8_t invertedGrayColorPalette[4] = {0, 0x6, 0xc, 0xf};
const uint8_t *grayColors = iBG == BBEP_BLACK ? invertedGrayColorPalette : grayColorPalette; // invert the gray table if we're on a black background
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@alexfaria alexfaria Apr 14, 2026

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I think these 3 const declarations could be moved outside of the while loop on line 1072 as iBG stays unchanged

Kept it as is but happy to make the change if you want

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@bitbank2 bitbank2 Apr 14, 2026 •
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That's an improvement. The const values appearing in the main loop has no effect on how the code is generated. Const are kept in a different memory segment. The compiler makes them go out of scope, but they don't get generated/removed each time the code is called. I'll test this shortly and let you know.

int iLineSize = (tw+7)/8;
memset(u8Cache, 0, iLineSize*2); // start with 2 lines of white (gray table is inverted)
for (ty=dy; ty<end_y+1 && ty+1 < height; ty++) {
uint8_t u8, u8Count, u8Color;
g5_decode_line(&g5dec, &u8Cache[(ty & 1) * iLineSize]);
if (w & 7) {
u8Cache[(ty & 1) * iLineSize + iLineSize - 1] &= u8EndMask;
}
if (ty & 1 && ty/2 >= 0) {
Scale2Gray(u8Cache, iLineSize, iLineSize); // convert a pair of lines
s = u8Cache;
u8 = *s++; // grab first byte
u8Count = 4;
for (tx=x+x_off; tx<x+x_off+tw && tx < width; tx+=2) {
u8Color = grayColors[u8>>6];
(*pBBEP->pfnSetPixelFast)(pBBEP, tx/2, ty/2, u8Color);
if (u8Color != iBG) {
// draw the pixel if it's not transparent
// avoid overlapping the previous character's pixels if the font is Italic for example
(*pBBEP->pfnSetPixelFast)(pBBEP, tx/2, ty/2, u8Color);
}
u8 <<= 2;
u8Count--;
if (u8Count == 0) {
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