Cómo convertir una image en matriz de bytes hexadecimales para enviarla a la secuencia de salida en iOS SDK

Quería imprimir una image en una impresora bluetooth. Obtuve un código de muestra por el fabricante de la impresora. Aquí está el código:

unsigned char buffer3[796]={ 0x55 , 0x66 , 0x77 , 0x88 , 0x44 , 0x1B , 0x58 , 0x31 , 0x19, 0x20, 0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x80 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x01 ,0xC0 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x01 ,0x80 ,0x00 ,0x03 ,0x60 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x03 ,0xA0 ,0x00 ,0x07 ,0xB0 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x05 ,0x60 ,0x00 ,0x07 ,0xD8 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x05 ,0xA0 ,0x00 ,0x13 ,0xEC ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x04 ,0x20 ,0x00 ,0x29 ,0xF4 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x03 ,0xC0 ,0x00 ,0x64 ,0xF9 ,0x00 ,0x0F ,0xFF ,0x9C ,0x01 ,0xC0 ,0x19 ,0xFF ,0xC0 ,0x7F ,0xFC ,0x7F ,0xF9 ,0xC0 ,0x3D ,0xFF ,0xF1 ,0xFF ,0xE3 ,0xFF ,0xC0 ,0x00 ,0x00 ,0xF2 ,0x73 ,0x80 ,0x0F ,0xFF ,0x9C ,0x01 ,0xC0 ,0x19 ,0xFF ,0xC0 ,0x7F ,0xFE ,0x7F ,0xFD ,0xE0 ,0x3D ,0xFF ,0xF1 ,0xFF ,0xE3 ,0xFF ,0xC0 ,0x00 ,0x00 ,0x79 ,0x26 ,0xC0 ,0x0F ,0xFF ,0xDC ,0x01 ,0xC0 ,0x19 ,0xFF ,0xC0 ,0x7F ,0xFE ,0xFF ,0xFD ,0xF0 ,0x7D ,0xFF ,0xFB ,0xFF ,0xF7 ,0xFF ,0xE0 ,0x00 ,0x03 ,0x3C ,0x8F ,0x60 ,0x0C ,0x01 ,0xDC ,0x01 ,0xC0 ,0x19 ,0x80 ,0x00 ,0x70 ,0x0E ,0xE0 ,0x1D ,0xF0 ,0x7D ,0x80 ,0x3B ,0x80 ,0x77 ,0x00 ,0xE0 ,0x00 ,0x04 ,0x9E ,0x8F ,0xB0 ,0x0E ,0x01 ,0xDC ,0x01 ,0xC0 ,0x19 ,0x80 ,0x00 ,0x70 ,0x0E ,0xE0 ,0x1D ,0xF8 ,0xFD ,0x80 ,0x33 ,0x80 ,0x77 ,0x00 ,0xE0 ,0x00 ,0x0E ,0x4F ,0x27 ,0xD8 ,0x0F ,0xFF ,0x9C ,0x01 ,0xC0 ,0x19 ,0xFF ,0xC0 ,0x7F ,0xFC ,0xE0 ,0x1D ,0xF9 ,0xFD ,0xFF ,0xF3 ,0x80 ,0x77 ,0x00 ,0xE0 ,0x00 ,0x0F ,0x26 ,0x53 ,0xC8 ,0x0F ,0xFF ,0x9C ,0x01 ,0xC0 ,0x19 ,0xFF ,0xC0 ,0x7F ,0xFC ,0xEF ,0xFD ,0xDD ,0xDD ,0xFF ,0xF3 ,0x80 ,0x77 ,0x00 ,0xE0 ,0x00 ,0x07 ,0x90 ,0xC9 ,0xF0 ,0x0F ,0xFF ,0xDC ,0x01 ,0xC0 ,0x19 ,0xFF ,0xC0 ,0x7F ,0xFE ,0xEF ,0xFD ,0xDF ,0x9D ,0xFF ,0xFB ,0x80 ,0x77 ,0x00 ,0xE0 ,0x00 ,0x03 ,0xC9 ,0xE4 ,0xE0 ,0x0C ,0x00 ,0xDC ,0x01 ,0xC0 ,0x19 ,0x80 ,0x00 ,0x70 ,0x06 ,0xE7 ,0xFD ,0xCF ,0x9D ,0x80 ,0x3B ,0x80 ,0x77 ,0x00 ,0xE0 ,0x00 ,0x01 ,0xF0 ,0xF2 ,0x40 ,0x0E ,0x01 ,0xDC ,0x00 ,0xC0 ,0x19 ,0x80 ,0x00 ,0x70 ,0x0E ,0xE0 ,0x1D ,0xCF ,0x1D ,0x80 ,0x3B ,0x80 ,0x77 ,0x00 ,0xE0 ,0x00 ,0x00 ,0xE6 ,0x79 ,0x00 ,0x0F ,0xFF ,0xDF ,0xFC ,0xFF ,0xF9 ,0xFF ,0xC0 ,0x7F ,0xFE ,0xE0 ,0x1D ,0xC7 ,0x1D ,0xFF ,0xFB ,0xFF ,0xF7 ,0xFF ,0xE0 ,0x00 ,0x00 ,0x49 ,0x3D ,0x00 ,0x0F ,0xFF ,0x9F ,0xFC ,0xFF ,0xF9 ,0xFF ,0xC0 ,0x7F ,0xFE ,0xE0 ,0x1D ,0xC2 ,0x1D ,0xFF ,0xF1 ,0xFF ,0xE3 ,0xFF ,0xC0 ,0x00 ,0x00 ,0x1C ,0x9E ,0x00 ,0x0F ,0xFF ,0x1F ,0xFC ,0x7F ,0xE1 ,0xFF ,0xC0 ,0x7F ,0xFC ,0xE0 ,0x1D ,0xC0 ,0x1D ,0xFF ,0xE0 ,0xFF ,0xC1 ,0xFF ,0x80 ,0x00 ,0x00 ,0x1E ,0x4C ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x0F ,0x20 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x07 ,0x90 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x03 ,0xE0 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x01 ,0xC0 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x80 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 ,0x00 }; [[session outputStream] write:(const uint8_t *)buffer3 maxLength:796];//send print package 

Lo que quiero saber es cómo convertir la image en la matriz de búfer. Puedo imprimir text usando esa impresora y esta image también. Solo quiero saber cómo convertir otras imágenes en esta matriz de búfer para que pueda enviarla a la secuencia de salida.

¡Cualquier ayuda sería muy apreciada!

Actualización 1: intenté con el código de @Tim van Elsloo pero no funciona … ¿alguna otra idea?

    Supongo que la impresora no tomará ningún formatting de image. Sin embargo, aquí es cómo puedes convertir una image en una matriz de bytes, espero que esto te ayude:

     NSData *data = [NSData dataWithContentsOfFile:imagePath]; NSUInteger length = [data length]; Byte *bytes = (Byte*)malloc(length); memcpy(bytes, [data bytes], length); 

    Prueba esto:

     CGImageRef image = [yourUIImage CGImage]; CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); NSUInteger width = CGImageGetWidth(image); NSUInteger height = CGImageGetHeight(image); NSUInteger bytesPerPixel = 4; NSUInteger bytesPerRow = bytesPerPixel * width; NSUInteger bitsPerComponent = 8; int size = height*width*bytesPerPixel; printf("Size:%d\n",size); unsigned char *rawData = malloc(size); CGContextRef context = CGBitmapContextCreate(rawData,width,height,bitsPerComponent,bytesPerRow,colorSpace,kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big); CGColorSpaceRelease(colorSpace); CGContextDrawImage(context, CGRectMake(0,0,width,height),image); CGContextRelease(context); 

    Ahora, rawData es la información que necesita.

    Fuente: http://www.iphonedevsdk.com/forum/iphone-sdk-development/21806-convert-cgimage-uiimage.html

    Edit: tienes maxLength:796 en tu código, pero estoy bastante seguro de que esto depende de la image en particular, probablemente deberías replace 796 por algo así como sizeof(rawData) .