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#include "cairodriver.h"
void read_ppm(void)
{
char *mask_name = G_store(file_name);
FILE *input, *mask;
int x, y;
int i_width, i_height, maxval;
input = fopen(file_name, "rb");
if (!input)
G_fatal_error("cairo: couldn't open input file %s", file_name);
if (fscanf(input, "P6 %d %d %d", &i_width, &i_height, &maxval) != 3)
G_fatal_error("cairo: invalid input file %s", file_name);
fgetc(input);
if (i_width != width || i_height != height)
G_fatal_error
("cairo: input file has incorrect dimensions: expected: %dx%d got: %dx%d",
width, height, i_width, i_height);
mask_name[strlen(mask_name) - 2] = 'g';
mask = fopen(mask_name, "rb");
if (!mask)
G_fatal_error("cairo: couldn't open input mask file %s", mask_name);
if (fscanf(mask, "P5 %d %d %d", &i_width, &i_height, &maxval) != 3)
G_fatal_error("cairo: invalid input mask file %s", mask_name);
fgetc(mask);
if (i_width != width || i_height != height)
G_fatal_error
("cairo: input mask file has incorrect dimensions: expected: %dx%d got: %dx%d",
width, height, i_width, i_height);
G_free(mask_name);
for (y = 0; y < height; y++) {
unsigned int *row = (unsigned int *)(grid + y * stride);
for (x = 0; x < width; x++) {
int r = fgetc(input);
int g = fgetc(input);
int b = fgetc(input);
int a = fgetc(mask);
r = r * 255 / maxval;
g = g * 255 / maxval;
b = b * 255 / maxval;
a = a * 255 / maxval;
if (a > 0 && a < 0xFF) {
r = r * a / 0xFF;
g = g * a / 0xFF;
b = b * a / 0xFF;
}
row[x] = (a << 24) | (r << 16) | (g << 8) | (b << 0);
}
}
fclose(input);
fclose(mask);
}
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