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#include "picture.h"
#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>
Picture new_picture(int width, int height) {
Picture ret;
ret.width = width;
ret.height = height;
ret.buffer = malloc(sizeof(float) * width * height * 3);
return ret;
}
void delete_picture(Picture pic) {
free(pic.buffer);
}
Color get_pixel(Picture pic, Vec2i pos) {
int idx = pos.y * pic.width * 3 + pos.x * 3;
return (Color) { pic.buffer[idx+2], pic.buffer[idx+1], pic.buffer[idx] };
}
void set_pixel(Picture pic, Vec2i pos, Color c) {
int idx = pos.y * pic.width * 3 + pos.x * 3;
pic.buffer[idx] = c.b;
pic.buffer[idx+1] = c.g;
pic.buffer[idx+2] = c.r;
}
void normalize_picture(Picture pic) {
float maxval = 0;
for (size_t i = 0; i < pic.width * pic.height * 3; i++) {
float val = pic.buffer[i];
if (val < 0) val = 0;
if (val > maxval) maxval = val;
}
if (maxval < 1.0) return;
for (size_t i = 0; i < pic.width * pic.height * 3; i++) {
pic.buffer[i] = pic.buffer[i] / maxval;
}
}
Picture picture_downscale_2x(Picture pic) {
Picture newpic = new_picture(pic.width / 2, pic.height / 2);
for (int x = 0; x < newpic.width; x++) {
for (int y = 0; y < newpic.height; y++) {
Color pixels[4];
pixels[0] = get_pixel(pic, (Vec2i){2*x, 2*y});
pixels[1] = get_pixel(pic, (Vec2i){2*x+1, 2*y});
pixels[2] = get_pixel(pic, (Vec2i){2*x, 2*y+1});
pixels[3] = get_pixel(pic, (Vec2i){2*x+1, 2*y+1});
set_pixel(newpic, (Vec2i){x,y}, pixel_avg4(pixels));
}
}
return newpic;
}
static bool fwrite_word16le(FILE* fp, uint16_t x) {
uint8_t buf[2];
buf[0] = x & 0xff;
buf[1] = (x >> 8) & 0xff;
int r = fwrite(buf, 1, 2, fp);
if (r != 2) return false;
return true;
}
static bool fwrite_word32le(FILE* fp, uint32_t x) {
bool ret = false;
uint16_t buf[2];
buf[0] = x & 0xffff;
buf[1] = (x >> 16) & 0xffff;
ret = fwrite_word16le(fp, buf[0]);
if (!ret) return ret;
ret = fwrite_word16le(fp, buf[1]);
if (!ret) return ret;
return true;
}
bool writeBMP(const char* filename, Picture pic) {
bool ret = false;
FILE *fp = NULL;
uint8_t *databuf = NULL;
fp = fopen(filename, "wb");
if (!fp) goto end;
int row_data_len = 3 * pic.width;
int padding = (4 - row_data_len % 4) % 4;
int row_len = row_data_len + padding;
int img_len = row_len * pic.height;
int file_len = 53 + img_len;
ret = fwrite_word16le(fp, 0x4d42);
if (!ret) goto end;
ret = fwrite_word32le(fp, file_len);
if (!ret) goto end;
ret = fwrite_word32le(fp, 0);
if (!ret) goto end;
ret = fwrite_word32le(fp, 54);
if (!ret) goto end;
ret = fwrite_word32le(fp, 40);
if (!ret) goto end;
ret = fwrite_word32le(fp, pic.width);
if (!ret) goto end;
ret = fwrite_word32le(fp, -pic.height);
if (!ret) goto end;
ret = fwrite_word16le(fp, 1);
if (!ret) goto end;
ret = fwrite_word16le(fp, 24);
if (!ret) goto end;
ret = fwrite_word32le(fp, 0); // BI_RGB
if (!ret) goto end;
ret = fwrite_word32le(fp, img_len);
if (!ret) goto end;
ret = fwrite_word32le(fp, 0);
if (!ret) goto end;
ret = fwrite_word32le(fp, 0);
if (!ret) goto end;
ret = fwrite_word32le(fp, 0);
if (!ret) goto end;
ret = fwrite_word32le(fp, 0);
if (!ret) goto end;
databuf = malloc(img_len);
memset(databuf, 0, img_len);
for (int i = 0; i < pic.height; i++) {
for (int j = 0; j < pic.width * 3; j++) {
int fromidx = i * pic.width * 3 + j;
int toidx = i * row_len + j;
float value = pic.buffer[fromidx];
if (value < 0) databuf[toidx] = 0;
else if (value > 1.0) {
databuf[toidx] = 255;
} else databuf[toidx] = 255 * value;
}
}
if (fwrite(databuf, 1, img_len, fp) != img_len) {
ret = false;
goto end;
}
ret = true;
end:
if (databuf != NULL) free(databuf);
if (fp != NULL) fclose(fp);
return ret;
}
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