Pandora
7 years ago
7 changed files with 167 additions and 7 deletions
@ -1,3 +0,0 @@ |
|||
Please do not send/request features related to image manipulation. i3lock’s |
|||
support for background images is intentionally kept minimal, you should do all |
|||
pre-processing in external tools. |
|||
@ -0,0 +1,117 @@ |
|||
#include <stdlib.h> |
|||
#include <inttypes.h> |
|||
#include <string.h> |
|||
#include <stdbool.h> |
|||
#include <stdio.h> |
|||
#include <err.h> |
|||
#include <errno.h> |
|||
#include <cairo.h> |
|||
#include <jpeglib.h> |
|||
|
|||
#include "jpg.h" |
|||
|
|||
/*
|
|||
* Checks if the file is a JPEG by looking for a valid JPEG header. |
|||
*/ |
|||
bool file_is_jpg(char* file_path) { |
|||
FILE* image_file; |
|||
uint16_t file_header; |
|||
size_t read_count; |
|||
// TODO: Consider endianess on non-x86 platforms
|
|||
uint16_t jpg_magick = 0xd8ff; |
|||
|
|||
image_file = fopen(file_path, "rb"); |
|||
if (image_file == NULL) { |
|||
int img_err = errno; |
|||
fprintf(stderr, "Could not open image file %s: %s\n", |
|||
file_path, strerror(img_err)); |
|||
return false; |
|||
} |
|||
|
|||
read_count = fread(&file_header, sizeof(file_header), 1, image_file); |
|||
fclose(image_file); |
|||
|
|||
if (read_count < 1) { |
|||
fprintf(stderr, "Error searching for JPEG header in %s\n", file_path); |
|||
return false; |
|||
} |
|||
|
|||
return file_header == jpg_magick; |
|||
} |
|||
|
|||
/*
|
|||
* Reads a JPEG from a file into memory, in a format that Cairo can create a |
|||
* surface from. |
|||
*/ |
|||
void* read_JPEG_file(char *file_path, JPEG_INFO *jpg_info) { |
|||
int img_err; |
|||
struct jpeg_decompress_struct cinfo; |
|||
struct jpeg_error_mgr jerr; |
|||
FILE *infile; /* source file */ |
|||
void *img; /* decompressed image data pointer */ |
|||
|
|||
if ((infile = fopen(file_path, "rb")) == NULL) { |
|||
img_err = errno; |
|||
fprintf(stderr, "Could not open image file %s: %s\n", |
|||
file_path, strerror(img_err)); |
|||
return NULL; |
|||
} |
|||
|
|||
cinfo.err = jpeg_std_error(&jerr); |
|||
jpeg_create_decompress(&cinfo); |
|||
|
|||
jpeg_stdio_src(&cinfo, infile); |
|||
|
|||
(void) jpeg_read_header(&cinfo, TRUE); |
|||
|
|||
// BGRA + endianness change = RGBA?
|
|||
// TODO: Test this code on non-x86_64 platforms
|
|||
cinfo.out_color_space = JCS_EXT_BGRA; |
|||
|
|||
(void) jpeg_start_decompress(&cinfo); |
|||
|
|||
jpg_info->height = cinfo.output_height; |
|||
jpg_info->width = cinfo.output_width; |
|||
|
|||
/* Get the *cairo* stride rather than the stride from the image. This is
|
|||
* the space needed in memory for each row for optimized Cairo rendering. */ |
|||
int cairo_stride = cairo_format_stride_for_width(CAIRO_FORMAT_ARGB32, |
|||
cinfo.output_width); |
|||
jpg_info->stride = cairo_stride; |
|||
if (cairo_stride < jpg_info->width) { |
|||
/* This should never happen, but if it does then the following code
|
|||
* will potentially write into unallocated memory */ |
|||
fprintf( |
|||
stderr, |
|||
"WARNING: Cairo stride shorter than JPEG width. Aborting JPEG read." |
|||
); |
|||
return NULL; |
|||
} |
|||
|
|||
// Allocate storage for the final, decompressed image.
|
|||
img = calloc(cairo_stride, cinfo.output_height); |
|||
if (img == NULL) { |
|||
fprintf(stderr, "Could not allocate memory for JPEG decode\n"); |
|||
|
|||
(void) jpeg_finish_decompress(&cinfo); |
|||
jpeg_destroy_decompress(&cinfo); |
|||
fclose(infile); |
|||
|
|||
return NULL; |
|||
} |
|||
|
|||
while (cinfo.output_scanline < cinfo.output_height) { |
|||
/* Normally, you would allocate a buffer using libJPEG's memory
|
|||
* management and write into it, but since we're reading one row at a |
|||
* time, we just write it directly into the image memory space */ |
|||
unsigned char* pos = img + (cairo_stride * (cinfo.output_scanline)); |
|||
(void) jpeg_read_scanlines(&cinfo, &pos, 1); |
|||
} |
|||
|
|||
(void) jpeg_finish_decompress(&cinfo); |
|||
|
|||
jpeg_destroy_decompress(&cinfo); |
|||
fclose(infile); |
|||
|
|||
return img; |
|||
} |
|||
@ -0,0 +1,21 @@ |
|||
#ifndef _JPG_H |
|||
#define _JPG_H |
|||
|
|||
typedef struct { |
|||
uint height; |
|||
uint width; |
|||
uint stride; // The width of each row in memory, in bytes
|
|||
} JPEG_INFO; |
|||
|
|||
/*
|
|||
* Checks if the file is a JPEG by looking for a valid JPEG header. |
|||
*/ |
|||
bool file_is_jpg(char* file_path); |
|||
|
|||
/*
|
|||
* Reads a JPEG from a file into memory, in a format that Cairo can create a |
|||
* surface from. |
|||
*/ |
|||
void* read_JPEG_file(char *filename, JPEG_INFO *jpg_info); |
|||
|
|||
#endif |
|||
Loading…
Reference in new issue