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Fix off by one error in OnDiskBitmap

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It resulted in the first row of pixels being pulled for out of bounds.

Fixes #1801
This commit is contained in:
Scott Shawcroft 2019-04-17 15:17:11 -07:00
parent 49c4c1e2ac
commit c372567330
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GPG Key ID: FD0EDC4B6C53CA59
1 changed files with 7 additions and 6 deletions
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13
shared-module/displayio/OnDiskBitmap.c
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@ -68,7 +68,7 @@ void common_hal_displayio_ondiskbitmap_construct(displayio_ondiskbitmap_t *self,
self->r_bitmask = read_word(bmp_header, 27); self->r_bitmask = read_word(bmp_header, 27);
self->g_bitmask = read_word(bmp_header, 29); self->g_bitmask = read_word(bmp_header, 29);
self->b_bitmask = read_word(bmp_header, 31); self->b_bitmask = read_word(bmp_header, 31);
} else { // no compression or short header means 5:5:5 } else { // no compression or short header means 5:5:5
self->r_bitmask = 0x7c00; self->r_bitmask = 0x7c00;
self->g_bitmask = 0x3e0; self->g_bitmask = 0x3e0;
@ -114,7 +114,7 @@ void common_hal_displayio_ondiskbitmap_construct(displayio_ondiskbitmap_t *self,
} }
self->stride = (bit_stride / 8); self->stride = (bit_stride / 8);
} }
} }
@ -123,12 +123,13 @@ uint32_t common_hal_displayio_ondiskbitmap_get_pixel(displayio_ondiskbitmap_t *s
if (x < 0 || x >= self->width || y < 0 || y >= self->height) { if (x < 0 || x >= self->width || y < 0 || y >= self->height) {
return 0; return 0;
} }
uint32_t location; uint32_t location;
uint8_t bytes_per_pixel = (self->bits_per_pixel / 8) ? (self->bits_per_pixel /8) : 1; uint8_t bytes_per_pixel = (self->bits_per_pixel / 8) ? (self->bits_per_pixel /8) : 1;
if (self->bits_per_pixel >= 8){ if (self->bits_per_pixel >= 8){
location = self->data_offset + (self->height - y) * self->stride + x * bytes_per_pixel; location = self->data_offset + (self->height - y - 1) * self->stride + x * bytes_per_pixel;
} else { } else {
location = self->data_offset + (self->height - y) * self->stride + x / 8; location = self->data_offset + (self->height - y - 1) * self->stride + x / 8;
} }
// We don't cache here because the underlying FS caches sectors. // We don't cache here because the underlying FS caches sectors.
f_lseek(&self->file->fp, location); f_lseek(&self->file->fp, location);
@ -140,7 +141,7 @@ uint32_t common_hal_displayio_ondiskbitmap_get_pixel(displayio_ondiskbitmap_t *s
uint8_t red; uint8_t red;
uint8_t green; uint8_t green;
uint8_t blue; uint8_t blue;
if (self->bits_per_pixel == 1){ if (self->bits_per_pixel == 1) {
uint8_t bit_offset = x%8; uint8_t bit_offset = x%8;
tmp = ( pixel_data & (0x80 >> (bit_offset))) >> (7 - bit_offset); tmp = ( pixel_data & (0x80 >> (bit_offset))) >> (7 - bit_offset);
if (tmp == 1) { if (tmp == 1) {
@ -148,7 +149,7 @@ uint32_t common_hal_displayio_ondiskbitmap_get_pixel(displayio_ondiskbitmap_t *s
} else { } else {
return 0x00000000; return 0x00000000;
} }
} else if (bytes_per_pixel == 1){ } else if (bytes_per_pixel == 1) {
blue = ((self->palette_data[pixel_data] & 0xFF) >> 0); blue = ((self->palette_data[pixel_data] & 0xFF) >> 0);
red = ((self->palette_data[pixel_data] & 0xFF0000) >> 16); red = ((self->palette_data[pixel_data] & 0xFF0000) >> 16);
green = ((self->palette_data[pixel_data] & 0xFF00) >> 8); green = ((self->palette_data[pixel_data] & 0xFF00) >> 8);