defocus-modules/lib/image.c

#include <defocus/image.h>

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define STB_IMAGE_IMPLEMENTATION
#include <stb_image.h>

#define STB_IMAGE_WRITE_IMPLEMENTATION
#include <stb_image_write.h>

struct df_image
{
    int width;
    int height;
    uint8_t *pixels;
};

DF_API df_result df_create_image(int w, int h, df_image **out_image)
{
    df_image *img = malloc(sizeof(df_image));
    if (!img)
        return df_result_out_of_memory;
    DF_ZERO_STRUCT(img);

    img->width = w;
    img->height = h;
    img->pixels = malloc(4 * sizeof(uint8_t) * w * h);
    if (!img->pixels) {
        free(img);
        return df_result_out_of_memory;
    }
    memset(img->pixels, 0, 4 * w * h);

    *out_image = img;
    return df_result_success;
}

DF_API df_result df_load_image(const char *path, int *out_w, int *out_h, df_image **out_image)
{
    int w, h, c;
    stbi_uc *pixels = stbi_load(path, &w, &h, &c, 4);
    if (!pixels) {
        fprintf(stderr, "ERROR: failed to load %s: %s\n", path, stbi_failure_reason());
        return df_result_io_error;
    }

    df_result res = df_result_success;
    df_image *img = malloc(sizeof(df_image));
    if (!img) {
        res = df_result_out_of_memory;
        goto err;
    }
    DF_ZERO_STRUCT(img);

    img->width = w;
    img->height = h;
    img->pixels = (uint8_t *)pixels;

    *out_image = img;
    *out_w = w;
    *out_h = h;

    goto out;
err:
    free(img);
out:
    return res;
}

DF_API void df_release_image(df_image *img)
{
    if (img) {
        free(img->pixels);
        free(img);
    }
}

DF_API df_result df_write_image(df_image *image, const char *path)
{
    df_result res = stbi_write_png(path, image->width, image->height, 4, image->pixels, image->width * 4)
                        ? df_result_success
                        : df_result_io_error;
    return res;
}

DF_API void df_get_image_size(const df_image *image, int *w, int *h)
{
    if (w)
        *w = image->width;
    if (h)
        *h = image->height;
}

DF_API df_color df_get_image_pixel(const df_image *image, int x, int y)
{
    df_color c = {0, 0, 0, 255};
    if (x >= 0 && x < image->width && y >= 0 && y < image->height) {
        memcpy(&c.e[0], &image->pixels[4 * (y * image->width + x)], 4);
    }
    return c;
}

DF_API void df_set_image_pixel(df_image *image, int x, int y, df_color c)
{
    if (x >= 0 && x < image->width && y >= 0 && y < image->height) {
        memcpy(&image->pixels[4 * (y * image->width + x)], &c.e[0], 4);
    }
}