使用iPhone中的滑块进行图像处理

Question

有没有办法将亮度应用于uiimages。例如，我有一个UIImageView，里面有一个Uiimage。我想在没有使用GlImageprocessing的情况下在UISlider的帮助下操作亮度。

请帮我解决这个问题，请不要向我建议关于GlImage处理。我想不使用GlImageprocessing。

Answer 1

这里是代码： -

 CGImageRef inImage = currentImage.CGImage; 
     CFDataRef ref = CGDataProviderCopyData(CGImageGetDataProvider(inImage)); 
     UInt8 * buf = (UInt8 *) CFDataGetBytePtr(ref); 
     int length = CFDataGetLength(ref); 
     float value2 = (1+slider.value-0.5); 
     NSLog(@"%i",value); 
     for(int i=0; i<length; i+=4) 
     { 


      int r = i; 
      int g = i+1; 
      int b = i+2; 

      int red = buf[r]; 
      int green = buf[g]; 
      int blue = buf[b]; 


      buf[r] = SAFECOLOR(red*value2); 
      buf[g] = SAFECOLOR(green*value2); 
      buf[b] = SAFECOLOR(blue*value2); 
     } 

     CGContextRef ctx = CGBitmapContextCreate(buf, 
               CGImageGetWidth(inImage), 
               CGImageGetHeight(inImage), 
               CGImageGetBitsPerComponent(inImage), 
               CGImageGetBytesPerRow(inImage), 
               CGImageGetColorSpace(inImage), 
               CGImageGetAlphaInfo(inImage)); 

     CGImageRef img = CGBitmapContextCreateImage(ctx); 

     [photoEditView setImage:[UIImage imageWithCGImage:img]]; 
     CFRelease(ref); 
     CGContextRelease(ctx); 
     CGImageRelease(img); 

在上面定义的： -

 #define SAFECOLOR(color) MIN(255,MAX(0,color)) 

Answer 2

看一看苹果的演示应用程序GLImageProcessing ，它的真快：

Answer 3

开放Gl to UIImage创建

- （UIImage *）glToUIImage {

NSInteger myDataLength = 320 * 480 * 4; 
// allocate array and read pixels into it. 
GLubyte *buffer = (GLubyte *) malloc(myDataLength); 
glReadPixels(0, 0, 320, 480, GL_RGBA, GL_UNSIGNED_BYTE, buffer); 

// gl renders "upside down" so swap top to bottom into new array. 
// there's gotta be a better way, but this works. 
GLubyte *buffer2 = (GLubyte *) malloc(myDataLength); 
for(int y = 0; y <480; y++) 
{ 
    for(int x = 0; x <320 * 4; x++) 
    { 
     buffer2[(479 - y) * 320 * 4 + x] = buffer[y * 4 * 320 + x]; 
    } 
} 
// make data provider with data. 
CGDataProviderRef provider = CGDataProviderCreateWithData(
                  NULL, buffer2, myDataLength, NULL); 

// prep the ingredients 
int bitsPerComponent = 8; 
int bitsPerPixel = 32; 
int bytesPerRow = 4 * 320; 
CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB(); 

CGBitmapInfo bitmapInfo = kCGImageAlphaNone; 

CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault; 

// make the cgimage 
CGImageRef imageRef = CGImageCreate(320, 480, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider, NULL, NO, renderingIntent); 

// then make the uiimage from that 


UIImage *myImage = [UIImage imageWithCGImage:imageRef]; 
CGImageRelease(imageRef); 

//UIImageWriteToSavedPhotosAlbum(myImage,nil,nil,nil); 

[[NSUserDefaults standardUserDefaults] setObject:UIImageJPEGRepresentation(myImage,1) forKey:@"image"];  

return myImage; 

}