extras: framebuffer image viewer

extras/imgview/Makefile

@@ -0,0 +1,15 @@
+XCC=x86_64-astral-gcc
+DESTDIR=/
+PREFIX=/usr/
+
+all: imgview 
+
+imgview: main.o
+	$(XCC) $(LDFLAGS) -o $@ $<
+
+%.o: %.c
+	$(XCC) -c $(CFLAGS) -o $@ $<
+
+install:
+	mkdir -p $(DESTDIR)/$(PREFIX)/bin/
+	mv imgview $(DESTDIR)/$(PREFIX)/bin/imgview

extras/imgview/main.c

@@ -0,0 +1,83 @@
+#include <stdio.h>
+#define STB_IMAGE_IMPLEMENTATION
+#include "stb_image.h"
+#include <fcntl.h>
+#include <errno.h>
+#include <linux/ioctl.h>
+#include <linux/fb.h>
+#include <sys/mman.h>
+
+void usage(){
+	printf("Usage: imgview filename\n");
+	exit(0);
+}
+
+int main(int argc, char* argv[]){
+	if(argc != 2)
+		usage();
+	
+	int fbfd = open("/dev/fb0", O_RDWR);
+
+	if(fbfd == -1){
+		
+		int err = errno;
+
+		if(err == ENOENT){
+			fprintf(stderr, "/dev/fb0 was not found. Make sure there are framebuffers available!\n");
+		}
+		
+		fprintf(stderr, "imgview: failed to open /dev/fb0: %s", strerror(err));
+
+		return -1;
+
+	}
+	
+	struct fb_fix_screeninfo fbfs;
+	struct fb_var_screeninfo fbvs;
+
+	if(ioctl(fbfd, FBIOGET_VSCREENINFO, &fbvs) == -1 || ioctl(fbfd, FBIOGET_FSCREENINFO, &fbfs) == -1){
+		perror("imgview: ioctl on framebuffer failed");
+		return -1;
+	}
+	
+	if(fbvs.bits_per_pixel != 24 && fbvs.bits_per_pixel != 32){
+		fprintf(stderr, "imgview: unsupported bpp!\n");
+		return -1;
+	}
+
+	size_t bypp = fbvs.bits_per_pixel / 8;
+
+	size_t memsize = fbfs.line_length * fbvs.yres;
+	
+	void* fbmap = mmap(NULL, memsize, PROT_WRITE | PROT_READ, MAP_SHARED, fbfd, 0);
+	if(fbmap == MAP_FAILED){
+		perror("imgview: mmap failed on framebuffer");
+		return -1;
+	}
+
+	int width, height, bytesperpixel;
+
+	char* data = stbi_load(argv[1], &width, &height, &bytesperpixel, 3);
+	
+	if(data == NULL){
+		fprintf(stderr, "imgview: failed to load %s\n", argv[1]);
+		return -1;
+	}
+
+	for(int y = 0; y < height; ++y){
+		for(int x = 0; x < width; ++x){
+			char* currentdata = data + x*bytesperpixel + y * width * bytesperpixel;
+			void* fbcurr = fbmap + x * bypp + y * fbfs.line_length;
+			
+			char d[3];
+
+			d[0] = currentdata[2];
+			d[1] = currentdata[1];
+			d[2] = currentdata[0];
+
+			memcpy(fbcurr, d, 3);
+		}
+	}
+
+
+}

recipes/imgview

@@ -0,0 +1,22 @@
+name=imgview
+revision=1
+from_source=imgview
+imagedeps="base-devel"
+hostdeps="gcc-cross binutils-cross"
+deps="mlibc"
+
+configure() {
+	true
+}
+
+build() {
+
+	make -C ${source_dir} -j ${parallelism}
+
+}
+
+install() {
+
+	make -C ${source_dir} install DESTDIR=${dest_dir}
+
+}

source-recipes/imgview

@@ -0,0 +1,7 @@
+name=imgview
+version=0
+source_dir="extras/imgview"
+
+regenerate() {
+	true
+}