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Use rounding to try to preserve the original value. Fix test case.

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This commit is contained in:
Jorge Rodriguez 2014-09-09 12:16:23 -07:00
parent 145690788c
commit ca241daefa
2 changed files with 9 additions and 9 deletions
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16
stb_image_resize.h
View File

@ -1210,7 +1210,7 @@ static void stbir__encode_scanline(stbir__info* stbir_info, int num_pixels, void
int encode_pixel_index = x*channels; int encode_pixel_index = x*channels;
for (n = 0; n < channels; n++) for (n = 0; n < channels; n++)
((unsigned char*)output_buffer)[output_pixel_index + n] = (unsigned char)(stbir__saturate(encode_buffer[encode_pixel_index + n]) * 255); ((unsigned char*)output_buffer)[output_pixel_index + n] = (unsigned char)(round(stbir__saturate(encode_buffer[encode_pixel_index + n]) * 255));
} }
break; break;
@ -1225,7 +1225,7 @@ static void stbir__encode_scanline(stbir__info* stbir_info, int num_pixels, void
((unsigned char*)output_buffer)[output_pixel_index + n] = stbir__linear_to_srgb_uchar(encode_buffer[encode_pixel_index + n]); ((unsigned char*)output_buffer)[output_pixel_index + n] = stbir__linear_to_srgb_uchar(encode_buffer[encode_pixel_index + n]);
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE)) if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
((unsigned char*)output_buffer)[output_pixel_index + alpha_channel] = (unsigned char)(stbir__saturate(encode_buffer[encode_pixel_index + alpha_channel]) * 255); ((unsigned char*)output_buffer)[output_pixel_index + alpha_channel] = (unsigned char)(round(stbir__saturate(encode_buffer[encode_pixel_index + alpha_channel]) * 255));
} }
break; break;
@ -1236,7 +1236,7 @@ static void stbir__encode_scanline(stbir__info* stbir_info, int num_pixels, void
int encode_pixel_index = x*channels; int encode_pixel_index = x*channels;
for (n = 0; n < channels; n++) for (n = 0; n < channels; n++)
((unsigned short*)output_buffer)[output_pixel_index + n] = (unsigned short)(stbir__saturate(encode_buffer[encode_pixel_index + n]) * 65535); ((unsigned short*)output_buffer)[output_pixel_index + n] = (unsigned short)(round(stbir__saturate(encode_buffer[encode_pixel_index + n]) * 65535));
} }
break; break;
@ -1247,10 +1247,10 @@ static void stbir__encode_scanline(stbir__info* stbir_info, int num_pixels, void
int encode_pixel_index = x*channels; int encode_pixel_index = x*channels;
for (n = 0; n < channels; n++) for (n = 0; n < channels; n++)
((unsigned short*)output_buffer)[output_pixel_index + n] = (unsigned short)(stbir__linear_to_srgb(stbir__saturate(encode_buffer[encode_pixel_index + n])) * 65535); ((unsigned short*)output_buffer)[output_pixel_index + n] = (unsigned short)(round(stbir__linear_to_srgb(stbir__saturate(encode_buffer[encode_pixel_index + n])) * 65535));
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE)) if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
((unsigned short*)output_buffer)[output_pixel_index + alpha_channel] = (unsigned char)(stbir__saturate(encode_buffer[encode_pixel_index + alpha_channel]) * 255); ((unsigned short*)output_buffer)[output_pixel_index + alpha_channel] = (unsigned short)(round(stbir__saturate(encode_buffer[encode_pixel_index + alpha_channel]) * 65535));
} }
break; break;
@ -1262,7 +1262,7 @@ static void stbir__encode_scanline(stbir__info* stbir_info, int num_pixels, void
int encode_pixel_index = x*channels; int encode_pixel_index = x*channels;
for (n = 0; n < channels; n++) for (n = 0; n < channels; n++)
((unsigned int*)output_buffer)[output_pixel_index + n] = (unsigned int)(((double)stbir__saturate(encode_buffer[encode_pixel_index + n])) * 4294967295); ((unsigned int*)output_buffer)[output_pixel_index + n] = (unsigned int)(round(((double)stbir__saturate(encode_buffer[encode_pixel_index + n])) * 4294967295));
} }
break; break;
@ -1273,10 +1273,10 @@ static void stbir__encode_scanline(stbir__info* stbir_info, int num_pixels, void
int encode_pixel_index = x*channels; int encode_pixel_index = x*channels;
for (n = 0; n < channels; n++) for (n = 0; n < channels; n++)
((unsigned int*)output_buffer)[output_pixel_index + n] = (unsigned int)(((double)stbir__linear_to_srgb(stbir__saturate(encode_buffer[encode_pixel_index + n]))) * 4294967295); ((unsigned int*)output_buffer)[output_pixel_index + n] = (unsigned int)(round(((double)stbir__linear_to_srgb(stbir__saturate(encode_buffer[encode_pixel_index + n]))) * 4294967295));
if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE)) if (!(stbir_info->flags&STBIR_FLAG_ALPHA_USES_COLORSPACE))
((unsigned int*)output_buffer)[output_pixel_index + alpha_channel] = (unsigned int)(((double)stbir__saturate(encode_buffer[encode_pixel_index + alpha_channel])) * 4294967295); ((unsigned int*)output_buffer)[output_pixel_index + alpha_channel] = (unsigned int)(round(((double)stbir__saturate(encode_buffer[encode_pixel_index + alpha_channel])) * 4294967295));
} }
break; break;

2
tests/resample_test.cpp
View File

@ -563,7 +563,7 @@ void verify_box(void)
STBIR_ASSERT(output44[j][i] == ((n+2)>>2)); STBIR_ASSERT(output44[j][i] == ((n+2)>>2));
t += n; t += n;
} }
STBIR_ASSERT(output11[j][i] == ((t+32)>>6)); STBIR_ASSERT(output11[0][0] == ((t+32)>>6));
} }
void verify_filter_normalized(stbir_filter filter, unsigned char* output, int output_size) void verify_filter_normalized(stbir_filter filter, unsigned char* output, int output_size)