Implement QOI image format #10
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Rangi42
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| @@ -0,0 +1,59 @@ | |||
| #include "proto.h" | |||
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| #define pixelcolor(px) (((uint32_t) (px).a << 24) | ((uint32_t) (px).b << 16) | ((uint32_t) (px).g << 8) | (uint32_t) (px).r) | |||
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I know this is basically PLUM_COLOR_VALUE_32, but (a) then I'd have to do PLUM_COLOR_VALUE_32(px.r, px.g, px.b, px.a), and (b) none of your src files actually use any of the convenience macros in header/color.h anyway.
| @@ -147,3 +147,10 @@ struct PNM_image_header { | |||
| size_t datastart; | |||
| size_t datalength; | |||
| }; | |||
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| struct QOI_pixel { | |||
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I did consider using four local uint8_t variables, or one packed uint32_t, but the overall complexity and line count would be higher, as values need to be packed into a lookup table and then unpacked for per-channel manipulation.
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| #define pixelcolor(px) (((uint32_t) (px).a << 24) | ((uint32_t) (px).b << 16) | ((uint32_t) (px).g << 8) | (uint32_t) (px).r) | ||
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| void load_QOI_data (struct context * context, unsigned flags, size_t limit) { |
| prev = px; | ||
| } | ||
| } | ||
| output += byteappend(output, 0, 0, 0, 0, 0, 0, 0, 1); |
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I considered using a memset for the 0s and then *output = 1;, but it would be more lines.
| } | ||
| return node -> data; | ||
| } | ||
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| static inline bool bit_depth_less_than (uint32_t depth, uint32_t target) { | ||
| // formally "less than or equal to", but that would be a very long name |
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"bit_depth_lte" would be shorter and not need a clarifying comment.
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| @@ -51,6 +51,16 @@ static inline void * append_output_node (struct context * context, size_t size) | |||
| return node -> data; | |||
| } | |||
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| static inline void * resize_output_node (struct context * context, void * data, size_t size) { | |||
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The alternative I saw to "allocate one large-as-possible node and then shrink it after QOI compression is done" was "allocate lots of little nodes for every QOI chunk", and this seemed better.
| for (size_t cell = 0; cell < framesize; cell ++) { | ||
| struct QOI_pixel px = {.r = data[cell], .g = data[cell] >> 8, .b = data[cell] >> 16, .a = data[cell] >> 24}; |
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Other possibilities which would use an extra line:
uint32_t * dataend = data + framesize;
for (uint32_t * val = data; val < data; val ++) {
struct QOI_pixel px = {.r = *val, .g = *val >> 8, .b = *val >> 16, .a = *val >> 24};
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if (run == 62 || val == dataend - 1) { for (size_t cell = 0; cell < framesize; cell ++) {
uint32_t val = data[cell];
struct QOI_pixel px = {.r = val, .g = val >> 8, .b = val >> 16, .a = val >> 24};
...
if (run == 62 || cell == framesize - 1) {
Spec: https://qoiformat.org/qoi-specification.pdf
Tested on the PNG and QOI images in qoi_test_images.zip, and on mandelbrot.png for a large 32768x32768 test case that the reference encoder can't handle (it's limited to 400-megapixel input, whereas this implementation is not).
After this is merged, fuzz.c should be updated to handle QOI files.
After the next version is released, the qoi repo should be PRed to list libplum in the supporting software.
This pull request is free and unencumbered software released into the public domain, under the same Unlicense as libplum.