kolibrios/contrib/C_Layer/EXAMPLE/img_example/main.c

/* Written by turbocat2001 (Logaev Maxim) */

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <kos32sys.h>
#include <kolibri_gui.h>
#include <kolibri_libimg.h>

#define NEW_IMG_H 128 
#define NEW_IMG_W 128

#define IMG_H 256
#define IMG_W 256

Image *image_blend; // Create image struct

struct kolibri_system_colors sys_color_table;  // Create system colors table

char* load_img(char* fname, int32_t* read_sz){  // Image file upload function
    FILE *f = fopen(fname, "rb");
    if (!f) {
        printf("Can't open file: %s\n", fname);
        exit(0);
    }
    if (fseek(f, 0, SEEK_END)) {
        printf("Can't SEEK_END file: %s\n", fname);
        exit(0);
    }
    int filesize = ftell(f);
    rewind(f);
    char* fdata = malloc(filesize);
    if(!fdata) {
        printf("No memory for file %s\n", fname);
        exit(0);
    }
    *read_sz = fread(fdata, 1, filesize, f);
    if (ferror(f)) {
        printf("Error reading file %s\n", fname);
        exit(0);
    }
    fclose(f);
    return fdata;
}

void DrawGUI(){
    begin_draw();
	sys_create_window(10, 40, (IMG_W+NEW_IMG_W)+50, IMG_H+50, "Libimg", sys_color_table.work_area, 0x34);
	img_draw(image_blend, 10, 10, IMG_W*2, IMG_H , 0, 0);  // Draw blended image to window
    end_draw();
}

int main(){
    if (kolibri_libimg_init() == -1){
		printf("Error loading lib_img.obj\n");
        exit(0);
	}
	
	get_system_colors(&sys_color_table); // Get system colors theme
    
    uint32_t img_size; 
    void *file_data = load_img("logo.png", &img_size); // Get RAW data and size 
    
    Image* image = img_decode(file_data, img_size, 0); // Decode RAW data to Image data
    
    if (image->Type != IMAGE_BPP32) { 
        image = img_convert(image, NULL, IMAGE_BPP32, 0, 0); // Convert image to format BPP32
        if (!image) {
             printf("Сonvert error!: \n");  
             exit(0);
        }
    }
    
    image_blend = img_create(IMG_W+NEW_IMG_W, IMG_H, IMAGE_BPP32);  // Create an empty layer
    img_fill_color(image_blend, IMG_W+NEW_IMG_W, IMG_H, sys_color_table.work_area); // Fill the layer with one color
    img_blend(image_blend, image, 0, 0, 0, 0, IMG_W, IMG_H);  // Blending images to display the alpha channel. 
    /* Reduce image size from 256x256 to 128x128 */
    image = img_scale(image, 0, 0, IMG_W, IMG_H, NULL, LIBIMG_SCALE_STRETCH , LIBIMG_INTER_BILINEAR, NEW_IMG_W, NEW_IMG_H);
    img_blend(image_blend, image, 256, 0, 0, 0, NEW_IMG_W, NEW_IMG_H); 
    img_destroy(image);  // Destroy image structure
    free(file_data);  // Free allocated file_data buffer 
    
    set_wanted_events_mask(0xC0000027);
    
    /* Main event loop */
    while (1) {         
		switch(get_os_event()){
			case KOLIBRI_EVENT_REDRAW:
				DrawGUI();
				break;
			case KOLIBRI_EVENT_BUTTON:
				if (get_os_button() == 1){
                    return 0;
                }
				break;
        }
	}
	return 0;
}