[PATCH 2/5] gui: Add qoi image format
Jules Maselbas
jmaselbas at kalray.eu
Mon Jan 10 14:12:52 PST 2022
Signed-off-by: Jules Maselbas <jmaselbas at kalray.eu>
---
lib/gui/Kconfig | 5 +
lib/gui/Makefile | 1 +
lib/gui/qoi.c | 94 +++++++
lib/gui/qoi.h | 671 +++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 771 insertions(+)
create mode 100644 lib/gui/qoi.c
create mode 100644 lib/gui/qoi.h
diff --git a/lib/gui/Kconfig b/lib/gui/Kconfig
index 2625d9fb2f..f0263c71cc 100644
--- a/lib/gui/Kconfig
+++ b/lib/gui/Kconfig
@@ -16,6 +16,11 @@ config PNG
bool "png"
select ZLIB
+config QOI
+ bool "qoi"
+ help
+ Support for the Quite OK Image format
+
if PNG
choice
diff --git a/lib/gui/Makefile b/lib/gui/Makefile
index 31e66225d7..5ed190e9f8 100644
--- a/lib/gui/Makefile
+++ b/lib/gui/Makefile
@@ -1,5 +1,6 @@
obj-$(CONFIG_BMP) += bmp.o
obj-$(CONFIG_IMAGE_RENDERER) += image_renderer.o graphic_utils.o
+obj-$(CONFIG_QOI) += qoi.o
obj-$(CONFIG_PNG) += png.o
obj-$(CONFIG_LODEPNG) += png_lode.o lodepng.o
obj-$(CONFIG_PICOPNG) += png_pico.o picopng.o
diff --git a/lib/gui/qoi.c b/lib/gui/qoi.c
new file mode 100644
index 0000000000..f6c1bc1b94
--- /dev/null
+++ b/lib/gui/qoi.c
@@ -0,0 +1,94 @@
+#include <common.h>
+#include <errno.h>
+#include <malloc.h>
+#include <fb.h>
+#include <asm/byteorder.h>
+#include <gui/graphic_utils.h>
+#include <init.h>
+#include <gui/image_renderer.h>
+#include <asm/unaligned.h>
+
+#define QOI_NO_STDIO
+#define QOI_IMPLEMENTATION
+#include "qoi.h"
+
+static struct image *qoi_open(char *inbuf, int insize)
+{
+ struct image *img;
+ void *data;
+ qoi_desc qoi;
+
+ img = calloc(1, sizeof(*img));
+ if (!img)
+ return ERR_PTR(-ENOMEM);
+
+ data = qoi_decode(inbuf, insize, &qoi, 0);
+ if (!data) {
+ free(img);
+ return ERR_PTR(-ENOMEM);
+ }
+
+ img->data = data;
+ img->height = qoi.height;
+ img->width = qoi.width;
+ img->bits_per_pixel = qoi.channels * 8;
+
+ pr_debug("qoi: %d x %d x %d data at 0x%p\n", img->width, img->height,
+ img->bits_per_pixel, img->data);
+ return img;
+}
+
+static void qoi_close(struct image *img)
+{
+ free(img->data);
+}
+
+static int qoi_renderer(struct screen *sc, struct surface *s, struct image *img)
+{
+ int alpha = img->bits_per_pixel == (4 * 8);
+ int width = s->width;
+ int height = s->height;
+ int startx = s->x;
+ int starty = s->y;
+ void *buf;
+
+ if (s->width < 0)
+ width = img->width;
+ if (s->height < 0)
+ height = img->height;
+
+ if (startx < 0) {
+ startx = (sc->s.width - width) / 2;
+ if (startx < 0)
+ startx = 0;
+ }
+
+ if (starty < 0) {
+ starty = (sc->s.height - height) / 2;
+ if (starty < 0)
+ starty = 0;
+ }
+
+ width = min(width, sc->s.width - startx);
+ height = min(height, sc->s.height - starty);
+
+ buf = gui_screen_render_buffer(sc);
+
+ gu_rgba_blend(sc->info, img, buf, height, width, startx, starty, alpha);
+
+ return img->height;
+}
+
+static struct image_renderer qoi = {
+ .type = filetype_qoi,
+ .open = qoi_open,
+ .close = qoi_close,
+ .renderer = qoi_renderer,
+ .keep_file_data = 1,
+};
+
+static int qoi_init(void)
+{
+ return image_renderer_register(&qoi);
+}
+fs_initcall(qoi_init);
diff --git a/lib/gui/qoi.h b/lib/gui/qoi.h
new file mode 100644
index 0000000000..988f9edcb4
--- /dev/null
+++ b/lib/gui/qoi.h
@@ -0,0 +1,671 @@
+/*
+
+QOI - The "Quite OK Image" format for fast, lossless image compression
+
+Dominic Szablewski - https://phoboslab.org
+
+
+-- LICENSE: The MIT License(MIT)
+
+Copyright(c) 2021 Dominic Szablewski
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files(the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and / or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions :
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
+
+-- About
+
+QOI encodes and decodes images in a lossless format. Compared to stb_image and
+stb_image_write QOI offers 20x-50x faster encoding, 3x-4x faster decoding and
+20% better compression.
+
+
+-- Synopsis
+
+// Define `QOI_IMPLEMENTATION` in *one* C/C++ file before including this
+// library to create the implementation.
+
+#define QOI_IMPLEMENTATION
+#include "qoi.h"
+
+// Encode and store an RGBA buffer to the file system. The qoi_desc describes
+// the input pixel data.
+qoi_write("image_new.qoi", rgba_pixels, &(qoi_desc){
+ .width = 1920,
+ .height = 1080,
+ .channels = 4,
+ .colorspace = QOI_SRGB
+});
+
+// Load and decode a QOI image from the file system into a 32bbp RGBA buffer.
+// The qoi_desc struct will be filled with the width, height, number of channels
+// and colorspace read from the file header.
+qoi_desc desc;
+void *rgba_pixels = qoi_read("image.qoi", &desc, 4);
+
+
+
+-- Documentation
+
+This library provides the following functions;
+- qoi_read -- read and decode a QOI file
+- qoi_decode -- decode the raw bytes of a QOI image from memory
+- qoi_write -- encode and write a QOI file
+- qoi_encode -- encode an rgba buffer into a QOI image in memory
+
+See the function declaration below for the signature and more information.
+
+If you don't want/need the qoi_read and qoi_write functions, you can define
+QOI_NO_STDIO before including this library.
+
+This library uses malloc() and free(). To supply your own malloc implementation
+you can define QOI_MALLOC and QOI_FREE before including this library.
+
+This library uses memset() to zero-initialize the index. To supply your own
+implementation you can define QOI_ZEROARR before including this library.
+
+
+-- Data Format
+
+A QOI file has a 14 byte header, followed by any number of data "chunks" and an
+8-byte end marker.
+
+struct qoi_header_t {
+ char magic[4]; // magic bytes "qoif"
+ uint32_t width; // image width in pixels (BE)
+ uint32_t height; // image height in pixels (BE)
+ uint8_t channels; // 3 = RGB, 4 = RGBA
+ uint8_t colorspace; // 0 = sRGB with linear alpha, 1 = all channels linear
+};
+
+Images are encoded row by row, left to right, top to bottom. The decoder and
+encoder start with {r: 0, g: 0, b: 0, a: 255} as the previous pixel value. An
+image is complete when all pixels specified by width * height have been covered.
+
+Pixels are encoded as
+ - a run of the previous pixel
+ - an index into an array of previously seen pixels
+ - a difference to the previous pixel value in r,g,b
+ - full r,g,b or r,g,b,a values
+
+The color channels are assumed to not be premultiplied with the alpha channel
+("un-premultiplied alpha").
+
+A running array[64] (zero-initialized) of previously seen pixel values is
+maintained by the encoder and decoder. Each pixel that is seen by the encoder
+and decoder is put into this array at the position formed by a hash function of
+the color value. In the encoder, if the pixel value at the index matches the
+current pixel, this index position is written to the stream as QOI_OP_INDEX.
+The hash function for the index is:
+
+ index_position = (r * 3 + g * 5 + b * 7 + a * 11) % 64
+
+Each chunk starts with a 2- or 8-bit tag, followed by a number of data bits. The
+bit length of chunks is divisible by 8 - i.e. all chunks are byte aligned. All
+values encoded in these data bits have the most significant bit on the left.
+
+The 8-bit tags have precedence over the 2-bit tags. A decoder must check for the
+presence of an 8-bit tag first.
+
+The byte stream's end is marked with 7 0x00 bytes followed a single 0x01 byte.
+
+
+The possible chunks are:
+
+
+.- QOI_OP_INDEX ----------.
+| Byte[0] |
+| 7 6 5 4 3 2 1 0 |
+|-------+-----------------|
+| 0 0 | index |
+`-------------------------`
+2-bit tag b00
+6-bit index into the color index array: 0..63
+
+A valid encoder must not issue 2 or more consecutive QOI_OP_INDEX chunks to the
+same index. QOI_OP_RUN should be used instead.
+
+
+.- QOI_OP_DIFF -----------.
+| Byte[0] |
+| 7 6 5 4 3 2 1 0 |
+|-------+-----+-----+-----|
+| 0 1 | dr | dg | db |
+`-------------------------`
+2-bit tag b01
+2-bit red channel difference from the previous pixel between -2..1
+2-bit green channel difference from the previous pixel between -2..1
+2-bit blue channel difference from the previous pixel between -2..1
+
+The difference to the current channel values are using a wraparound operation,
+so "1 - 2" will result in 255, while "255 + 1" will result in 0.
+
+Values are stored as unsigned integers with a bias of 2. E.g. -2 is stored as
+0 (b00). 1 is stored as 3 (b11).
+
+The alpha value remains unchanged from the previous pixel.
+
+
+.- QOI_OP_LUMA -------------------------------------.
+| Byte[0] | Byte[1] |
+| 7 6 5 4 3 2 1 0 | 7 6 5 4 3 2 1 0 |
+|-------+-----------------+-------------+-----------|
+| 1 0 | green diff | dr - dg | db - dg |
+`---------------------------------------------------`
+2-bit tag b10
+6-bit green channel difference from the previous pixel -32..31
+4-bit red channel difference minus green channel difference -8..7
+4-bit blue channel difference minus green channel difference -8..7
+
+The green channel is used to indicate the general direction of change and is
+encoded in 6 bits. The red and blue channels (dr and db) base their diffs off
+of the green channel difference and are encoded in 4 bits. I.e.:
+ dr_dg = (cur_px.r - prev_px.r) - (cur_px.g - prev_px.g)
+ db_dg = (cur_px.b - prev_px.b) - (cur_px.g - prev_px.g)
+
+The difference to the current channel values are using a wraparound operation,
+so "10 - 13" will result in 253, while "250 + 7" will result in 1.
+
+Values are stored as unsigned integers with a bias of 32 for the green channel
+and a bias of 8 for the red and blue channel.
+
+The alpha value remains unchanged from the previous pixel.
+
+
+.- QOI_OP_RUN ------------.
+| Byte[0] |
+| 7 6 5 4 3 2 1 0 |
+|-------+-----------------|
+| 1 1 | run |
+`-------------------------`
+2-bit tag b11
+6-bit run-length repeating the previous pixel: 1..62
+
+The run-length is stored with a bias of -1. Note that the run-lengths 63 and 64
+(b111110 and b111111) are illegal as they are occupied by the QOI_OP_RGB and
+QOI_OP_RGBA tags.
+
+
+.- QOI_OP_RGB ------------------------------------------.
+| Byte[0] | Byte[1] | Byte[2] | Byte[3] |
+| 7 6 5 4 3 2 1 0 | 7 .. 0 | 7 .. 0 | 7 .. 0 |
+|-------------------------+---------+---------+---------|
+| 1 1 1 1 1 1 1 0 | red | green | blue |
+`-------------------------------------------------------`
+8-bit tag b11111110
+8-bit red channel value
+8-bit green channel value
+8-bit blue channel value
+
+The alpha value remains unchanged from the previous pixel.
+
+
+.- QOI_OP_RGBA ---------------------------------------------------.
+| Byte[0] | Byte[1] | Byte[2] | Byte[3] | Byte[4] |
+| 7 6 5 4 3 2 1 0 | 7 .. 0 | 7 .. 0 | 7 .. 0 | 7 .. 0 |
+|-------------------------+---------+---------+---------+---------|
+| 1 1 1 1 1 1 1 1 | red | green | blue | alpha |
+`-----------------------------------------------------------------`
+8-bit tag b11111111
+8-bit red channel value
+8-bit green channel value
+8-bit blue channel value
+8-bit alpha channel value
+
+*/
+
+
+/* -----------------------------------------------------------------------------
+Header - Public functions */
+
+#ifndef QOI_H
+#define QOI_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/* A pointer to a qoi_desc struct has to be supplied to all of qoi's functions.
+It describes either the input format (for qoi_write and qoi_encode), or is
+filled with the description read from the file header (for qoi_read and
+qoi_decode).
+
+The colorspace in this qoi_desc is an enum where
+ 0 = sRGB, i.e. gamma scaled RGB channels and a linear alpha channel
+ 1 = all channels are linear
+You may use the constants QOI_SRGB or QOI_LINEAR. The colorspace is purely
+informative. It will be saved to the file header, but does not affect
+how chunks are en-/decoded. */
+
+#define QOI_SRGB 0
+#define QOI_LINEAR 1
+
+typedef struct {
+ unsigned int width;
+ unsigned int height;
+ unsigned char channels;
+ unsigned char colorspace;
+} qoi_desc;
+
+#ifndef QOI_NO_STDIO
+
+/* Encode raw RGB or RGBA pixels into a QOI image and write it to the file
+system. The qoi_desc struct must be filled with the image width, height,
+number of channels (3 = RGB, 4 = RGBA) and the colorspace.
+
+The function returns 0 on failure (invalid parameters, or fopen or malloc
+failed) or the number of bytes written on success. */
+
+int qoi_write(const char *filename, const void *data, const qoi_desc *desc);
+
+
+/* Read and decode a QOI image from the file system. If channels is 0, the
+number of channels from the file header is used. If channels is 3 or 4 the
+output format will be forced into this number of channels.
+
+The function either returns NULL on failure (invalid data, or malloc or fopen
+failed) or a pointer to the decoded pixels. On success, the qoi_desc struct
+will be filled with the description from the file header.
+
+The returned pixel data should be free()d after use. */
+
+void *qoi_read(const char *filename, qoi_desc *desc, int channels);
+
+#endif /* QOI_NO_STDIO */
+
+
+/* Encode raw RGB or RGBA pixels into a QOI image in memory.
+
+The function either returns NULL on failure (invalid parameters or malloc
+failed) or a pointer to the encoded data on success. On success the out_len
+is set to the size in bytes of the encoded data.
+
+The returned qoi data should be free()d after use. */
+
+void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len);
+
+
+/* Decode a QOI image from memory.
+
+The function either returns NULL on failure (invalid parameters or malloc
+failed) or a pointer to the decoded pixels. On success, the qoi_desc struct
+is filled with the description from the file header.
+
+The returned pixel data should be free()d after use. */
+
+void *qoi_decode(const void *data, int size, qoi_desc *desc, int channels);
+
+
+#ifdef __cplusplus
+}
+#endif
+#endif /* QOI_H */
+
+
+/* -----------------------------------------------------------------------------
+Implementation */
+
+#ifdef QOI_IMPLEMENTATION
+#include <stdlib.h>
+#include <string.h>
+
+#ifndef QOI_MALLOC
+ #define QOI_MALLOC(sz) malloc(sz)
+ #define QOI_FREE(p) free(p)
+#endif
+#ifndef QOI_ZEROARR
+ #define QOI_ZEROARR(a) memset((a),0,sizeof(a))
+#endif
+
+#define QOI_OP_INDEX 0x00 /* 00xxxxxx */
+#define QOI_OP_DIFF 0x40 /* 01xxxxxx */
+#define QOI_OP_LUMA 0x80 /* 10xxxxxx */
+#define QOI_OP_RUN 0xc0 /* 11xxxxxx */
+#define QOI_OP_RGB 0xfe /* 11111110 */
+#define QOI_OP_RGBA 0xff /* 11111111 */
+
+#define QOI_MASK_2 0xc0 /* 11000000 */
+
+#define QOI_COLOR_HASH(C) (C.rgba.r*3 + C.rgba.g*5 + C.rgba.b*7 + C.rgba.a*11)
+#define QOI_MAGIC \
+ (((unsigned int)'q') << 24 | ((unsigned int)'o') << 16 | \
+ ((unsigned int)'i') << 8 | ((unsigned int)'f'))
+#define QOI_HEADER_SIZE 14
+
+/* 2GB is the max file size that this implementation can safely handle. We guard
+against anything larger than that, assuming the worst case with 5 bytes per
+pixel, rounded down to a nice clean value. 400 million pixels ought to be
+enough for anybody. */
+#define QOI_PIXELS_MAX ((unsigned int)400000000)
+
+typedef union {
+ struct { unsigned char r, g, b, a; } rgba;
+ unsigned int v;
+} qoi_rgba_t;
+
+static const unsigned char qoi_padding[8] = {0,0,0,0,0,0,0,1};
+
+static void qoi_write_32(unsigned char *bytes, int *p, unsigned int v) {
+ bytes[(*p)++] = (0xff000000 & v) >> 24;
+ bytes[(*p)++] = (0x00ff0000 & v) >> 16;
+ bytes[(*p)++] = (0x0000ff00 & v) >> 8;
+ bytes[(*p)++] = (0x000000ff & v);
+}
+
+static unsigned int qoi_read_32(const unsigned char *bytes, int *p) {
+ unsigned int a = bytes[(*p)++];
+ unsigned int b = bytes[(*p)++];
+ unsigned int c = bytes[(*p)++];
+ unsigned int d = bytes[(*p)++];
+ return a << 24 | b << 16 | c << 8 | d;
+}
+
+void *qoi_encode(const void *data, const qoi_desc *desc, int *out_len) {
+ int i, max_size, p, run;
+ int px_len, px_end, px_pos, channels;
+ unsigned char *bytes;
+ const unsigned char *pixels;
+ qoi_rgba_t index[64];
+ qoi_rgba_t px, px_prev;
+
+ if (
+ data == NULL || out_len == NULL || desc == NULL ||
+ desc->width == 0 || desc->height == 0 ||
+ desc->channels < 3 || desc->channels > 4 ||
+ desc->colorspace > 1 ||
+ desc->height >= QOI_PIXELS_MAX / desc->width
+ ) {
+ return NULL;
+ }
+
+ max_size =
+ desc->width * desc->height * (desc->channels + 1) +
+ QOI_HEADER_SIZE + sizeof(qoi_padding);
+
+ p = 0;
+ bytes = (unsigned char *) QOI_MALLOC(max_size);
+ if (!bytes) {
+ return NULL;
+ }
+
+ qoi_write_32(bytes, &p, QOI_MAGIC);
+ qoi_write_32(bytes, &p, desc->width);
+ qoi_write_32(bytes, &p, desc->height);
+ bytes[p++] = desc->channels;
+ bytes[p++] = desc->colorspace;
+
+
+ pixels = (const unsigned char *)data;
+
+ QOI_ZEROARR(index);
+
+ run = 0;
+ px_prev.rgba.r = 0;
+ px_prev.rgba.g = 0;
+ px_prev.rgba.b = 0;
+ px_prev.rgba.a = 255;
+ px = px_prev;
+
+ px_len = desc->width * desc->height * desc->channels;
+ px_end = px_len - desc->channels;
+ channels = desc->channels;
+
+ for (px_pos = 0; px_pos < px_len; px_pos += channels) {
+ if (channels == 4) {
+ px = *(qoi_rgba_t *)(pixels + px_pos);
+ }
+ else {
+ px.rgba.r = pixels[px_pos + 0];
+ px.rgba.g = pixels[px_pos + 1];
+ px.rgba.b = pixels[px_pos + 2];
+ }
+
+ if (px.v == px_prev.v) {
+ run++;
+ if (run == 62 || px_pos == px_end) {
+ bytes[p++] = QOI_OP_RUN | (run - 1);
+ run = 0;
+ }
+ }
+ else {
+ int index_pos;
+
+ if (run > 0) {
+ bytes[p++] = QOI_OP_RUN | (run - 1);
+ run = 0;
+ }
+
+ index_pos = QOI_COLOR_HASH(px) % 64;
+
+ if (index[index_pos].v == px.v) {
+ bytes[p++] = QOI_OP_INDEX | index_pos;
+ }
+ else {
+ index[index_pos] = px;
+
+ if (px.rgba.a == px_prev.rgba.a) {
+ signed char vr = px.rgba.r - px_prev.rgba.r;
+ signed char vg = px.rgba.g - px_prev.rgba.g;
+ signed char vb = px.rgba.b - px_prev.rgba.b;
+
+ signed char vg_r = vr - vg;
+ signed char vg_b = vb - vg;
+
+ if (
+ vr > -3 && vr < 2 &&
+ vg > -3 && vg < 2 &&
+ vb > -3 && vb < 2
+ ) {
+ bytes[p++] = QOI_OP_DIFF | (vr + 2) << 4 | (vg + 2) << 2 | (vb + 2);
+ }
+ else if (
+ vg_r > -9 && vg_r < 8 &&
+ vg > -33 && vg < 32 &&
+ vg_b > -9 && vg_b < 8
+ ) {
+ bytes[p++] = QOI_OP_LUMA | (vg + 32);
+ bytes[p++] = (vg_r + 8) << 4 | (vg_b + 8);
+ }
+ else {
+ bytes[p++] = QOI_OP_RGB;
+ bytes[p++] = px.rgba.r;
+ bytes[p++] = px.rgba.g;
+ bytes[p++] = px.rgba.b;
+ }
+ }
+ else {
+ bytes[p++] = QOI_OP_RGBA;
+ bytes[p++] = px.rgba.r;
+ bytes[p++] = px.rgba.g;
+ bytes[p++] = px.rgba.b;
+ bytes[p++] = px.rgba.a;
+ }
+ }
+ }
+ px_prev = px;
+ }
+
+ for (i = 0; i < (int)sizeof(qoi_padding); i++) {
+ bytes[p++] = qoi_padding[i];
+ }
+
+ *out_len = p;
+ return bytes;
+}
+
+void *qoi_decode(const void *data, int size, qoi_desc *desc, int channels) {
+ const unsigned char *bytes;
+ unsigned int header_magic;
+ unsigned char *pixels;
+ qoi_rgba_t index[64];
+ qoi_rgba_t px;
+ int px_len, chunks_len, px_pos;
+ int p = 0, run = 0;
+
+ if (
+ data == NULL || desc == NULL ||
+ (channels != 0 && channels != 3 && channels != 4) ||
+ size < QOI_HEADER_SIZE + (int)sizeof(qoi_padding)
+ ) {
+ return NULL;
+ }
+
+ bytes = (const unsigned char *)data;
+
+ header_magic = qoi_read_32(bytes, &p);
+ desc->width = qoi_read_32(bytes, &p);
+ desc->height = qoi_read_32(bytes, &p);
+ desc->channels = bytes[p++];
+ desc->colorspace = bytes[p++];
+
+ if (
+ desc->width == 0 || desc->height == 0 ||
+ desc->channels < 3 || desc->channels > 4 ||
+ desc->colorspace > 1 ||
+ header_magic != QOI_MAGIC ||
+ desc->height >= QOI_PIXELS_MAX / desc->width
+ ) {
+ return NULL;
+ }
+
+ if (channels == 0) {
+ channels = desc->channels;
+ }
+
+ px_len = desc->width * desc->height * channels;
+ pixels = (unsigned char *) QOI_MALLOC(px_len);
+ if (!pixels) {
+ return NULL;
+ }
+
+ QOI_ZEROARR(index);
+ px.rgba.r = 0;
+ px.rgba.g = 0;
+ px.rgba.b = 0;
+ px.rgba.a = 255;
+
+ chunks_len = size - (int)sizeof(qoi_padding);
+ for (px_pos = 0; px_pos < px_len; px_pos += channels) {
+ if (run > 0) {
+ run--;
+ }
+ else if (p < chunks_len) {
+ int b1 = bytes[p++];
+
+ if (b1 == QOI_OP_RGB) {
+ px.rgba.r = bytes[p++];
+ px.rgba.g = bytes[p++];
+ px.rgba.b = bytes[p++];
+ }
+ else if (b1 == QOI_OP_RGBA) {
+ px.rgba.r = bytes[p++];
+ px.rgba.g = bytes[p++];
+ px.rgba.b = bytes[p++];
+ px.rgba.a = bytes[p++];
+ }
+ else if ((b1 & QOI_MASK_2) == QOI_OP_INDEX) {
+ px = index[b1];
+ }
+ else if ((b1 & QOI_MASK_2) == QOI_OP_DIFF) {
+ px.rgba.r += ((b1 >> 4) & 0x03) - 2;
+ px.rgba.g += ((b1 >> 2) & 0x03) - 2;
+ px.rgba.b += ( b1 & 0x03) - 2;
+ }
+ else if ((b1 & QOI_MASK_2) == QOI_OP_LUMA) {
+ int b2 = bytes[p++];
+ int vg = (b1 & 0x3f) - 32;
+ px.rgba.r += vg - 8 + ((b2 >> 4) & 0x0f);
+ px.rgba.g += vg;
+ px.rgba.b += vg - 8 + (b2 & 0x0f);
+ }
+ else if ((b1 & QOI_MASK_2) == QOI_OP_RUN) {
+ run = (b1 & 0x3f);
+ }
+
+ index[QOI_COLOR_HASH(px) % 64] = px;
+ }
+
+ if (channels == 4) {
+ *(qoi_rgba_t*)(pixels + px_pos) = px;
+ }
+ else {
+ pixels[px_pos + 0] = px.rgba.r;
+ pixels[px_pos + 1] = px.rgba.g;
+ pixels[px_pos + 2] = px.rgba.b;
+ }
+ }
+
+ return pixels;
+}
+
+#ifndef QOI_NO_STDIO
+#include <stdio.h>
+
+int qoi_write(const char *filename, const void *data, const qoi_desc *desc) {
+ FILE *f = fopen(filename, "wb");
+ int size;
+ void *encoded;
+
+ if (!f) {
+ return 0;
+ }
+
+ encoded = qoi_encode(data, desc, &size);
+ if (!encoded) {
+ fclose(f);
+ return 0;
+ }
+
+ fwrite(encoded, 1, size, f);
+ fclose(f);
+
+ QOI_FREE(encoded);
+ return size;
+}
+
+void *qoi_read(const char *filename, qoi_desc *desc, int channels) {
+ FILE *f = fopen(filename, "rb");
+ int size, bytes_read;
+ void *pixels, *data;
+
+ if (!f) {
+ return NULL;
+ }
+
+ fseek(f, 0, SEEK_END);
+ size = ftell(f);
+ if (size <= 0) {
+ fclose(f);
+ return NULL;
+ }
+ fseek(f, 0, SEEK_SET);
+
+ data = QOI_MALLOC(size);
+ if (!data) {
+ fclose(f);
+ return NULL;
+ }
+
+ bytes_read = fread(data, 1, size, f);
+ fclose(f);
+
+ pixels = qoi_decode(data, bytes_read, desc, channels);
+ QOI_FREE(data);
+ return pixels;
+}
+
+#endif /* QOI_NO_STDIO */
+#endif /* QOI_IMPLEMENTATION */
--
2.17.1
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