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lib/fonts: Refactor glyph-pattern helpers

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Change the signatures of the pattern helpers to align them with other
font-glyph helpers: use the font_glyph_ prefix and pass the glyph
buffer first.

Calculating the position of the involved bit is somewhat obfuscated
in the original implementation. Move it into the new helper
__font_glyph_pos() and use the result as array index and bit position.

Note that these bit helpers use a bit pitch, while other code uses a
byte pitch. This is intentional and required here.

v2:
- fix typos in commit message

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>
This commit is contained in:
Thomas Zimmermann 2026-04-07 11:23:17 +02:00 committed by Helge Deller
parent bdfd943231
commit 6ad4ed8408
1 changed files with 27 additions and 18 deletions
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45
lib/fonts/font_rotate.c
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@ -15,21 +15,33 @@
#include "font.h"
static inline int pattern_test_bit(u32 x, u32 y, u32 pitch, const char *pat)
static unsigned int __font_glyph_pos(unsigned int x, unsigned int y, unsigned int bit_pitch,
unsigned int *bit)
{
u32 tmp = (y * pitch) + x, index = tmp / 8, bit = tmp % 8;
unsigned int off = y * bit_pitch + x;
unsigned int bit_shift = off % 8;
pat += index;
return (*pat) & (0x80 >> bit);
*bit = 0x80 >> bit_shift; /* MSB has position 0, LSB has position 7 */
return off / 8;
}
static inline void pattern_set_bit(u32 x, u32 y, u32 pitch, char *pat)
static bool font_glyph_test_bit(const unsigned char *glyph, unsigned int x, unsigned int y,
unsigned int bit_pitch)
{
u32 tmp = (y * pitch) + x, index = tmp / 8, bit = tmp % 8;
unsigned int bit;
unsigned int i = __font_glyph_pos(x, y, bit_pitch, &bit);
pat += index;
return glyph[i] & bit;
}
(*pat) |= 0x80 >> bit;
static void font_glyph_set_bit(unsigned char *glyph, unsigned int x, unsigned int y,
unsigned int bit_pitch)
{
unsigned int bit;
unsigned int i = __font_glyph_pos(x, y, bit_pitch, &bit);
glyph[i] |= bit;
}
static inline void rotate_cw(const char *in, char *out, u32 width, u32 height)
@ -42,9 +54,8 @@ static inline void rotate_cw(const char *in, char *out, u32 width, u32 height)
for (i = 0; i < h; i++) {
for (j = 0; j < w; j++) {
if (pattern_test_bit(j, i, width, in))
pattern_set_bit(height - 1 - i - shift, j,
height, out);
if (font_glyph_test_bit(in, j, i, width))
font_glyph_set_bit(out, height - 1 - i - shift, j, height);
}
}
}
@ -81,10 +92,9 @@ static inline void rotate_ud(const char *in, char *out, u32 width, u32 height)
for (i = 0; i < height; i++) {
for (j = 0; j < width - shift; j++) {
if (pattern_test_bit(j, i, width, in))
pattern_set_bit(width - (1 + j + shift),
height - (1 + i),
width, out);
if (font_glyph_test_bit(in, j, i, width))
font_glyph_set_bit(out, width - (1 + j + shift),
height - (1 + i), width);
}
}
}
@ -119,9 +129,8 @@ static inline void rotate_ccw(const char *in, char *out, u32 width, u32 height)
for (i = 0; i < h; i++) {
for (j = 0; j < w; j++) {
if (pattern_test_bit(j, i, width, in))
pattern_set_bit(i, width - 1 - j - shift,
height, out);
if (font_glyph_test_bit(in, j, i, width))
font_glyph_set_bit(out, i, width - 1 - j - shift, height);
}
}
}