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在iOS中使用棕褐色图像效果时出错?

effects uiimageview ios

Chandru · 技术社区 · 10 年前

在我的应用程序中,我有一个 imageView ,中的图像 图像视图 应该有一些像棕褐色、黑色和白色的效果。
为了实现棕褐色效果,我使用了以下代码:,

 -(UIImage*)makeSepiaScale:(UIImage*)image
{
    CGImageRef cgImage = [image CGImage];
    CGDataProviderRef provider = CGImageGetDataProvider(cgImage);
    CFDataRef bitmapData = CGDataProviderCopyData(provider);
    UInt8* data = (UInt8*)CFDataGetBytePtr(bitmapData);

    int imagWidth = image.size.width;
    int imageheight = image.size.height;
    NSInteger myDataLength = imagWidth * imageheight * 4;


    for (int i = 0; i < myDataLength; i+=4)
    {
        UInt8 r_pixel = data[i];
        UInt8 g_pixel = data[i+1];
        UInt8 b_pixel = data[i+2];

        int outputRed = (r_pixel * .393) + (g_pixel *.769) + (b_pixel * .189);
        int outputGreen = (r_pixel * .349) + (g_pixel *.686) + (b_pixel * .168);
        int outputBlue = (r_pixel * .272) + (g_pixel *.534) + (b_pixel * .131);

        if(outputRed>255)outputRed=255;
        if(outputGreen>255)outputGreen=255;
        if(outputBlue>255)outputBlue=255;


        data[i] = outputRed;
        data[i+1] = outputGreen;
        data[i+2] = outputBlue;
    }

    CGDataProviderRef provider2 = CGDataProviderCreateWithData(NULL, data, myDataLength, NULL);
    int bitsPerComponent = 8;
    int bitsPerPixel = 32;
    int bytesPerRow = 4 * imagWidth;
    CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();
    CGBitmapInfo bitmapInfo = kCGBitmapByteOrderDefault;
    CGColorRenderingIntent renderingIntent = kCGRenderingIntentDefault;
    CGImageRef imageRef = CGImageCreate(imagWidth, imageheight, bitsPerComponent, bitsPerPixel, bytesPerRow, colorSpaceRef, bitmapInfo, provider2, NULL, NO, renderingIntent);

    CGColorSpaceRelease(colorSpaceRef); // YOU CAN RELEASE THIS NOW
    CGDataProviderRelease(provider2); // YOU CAN RELEASE THIS NOW
    CFRelease(bitmapData);

    UIImage *sepiaImage = [UIImage imageWithCGImage:imageRef];
    CGImageRelease(imageRef); // YOU CAN RELEASE THIS NOW
    return sepiaImage;
}

它工作得很好,但仅适用于.png图像,当我使用.jpg图像时,它只显示 图像视图 。如有任何帮助,将不胜感激

3 回复 | 直到 10 年前

chandru 10 年前

使用核心图像处理,

 -(void)makeSepiaScale
{
CIImage *beginImage =[[CIImage alloc]initWithImage:imageForView];

    CIContext * context=[CIContext contextWithOptions:nil];

    CIFilter *filter = [CIFilter filterWithName:@"CISepiaTone"
                                  keysAndValues: kCIInputImageKey, beginImage,
                        @"inputIntensity", @0.8, nil];
    CIImage *outImage = [filter outputImage];

    CGImageRef cgimg=[context createCGImage:outImage fromRect:[outImage extent]];


[imageView setImage:[UIImage imageWithCGImage:cgimg]];

}

Oleg Vit'ko 10 年前

使用CGImageCreateWithJPEGDataProvider从JPEG获取位图:

-(UIImage*)makeSepiaScale:(UIImage*)image {

    CGImageRef cgJpegImage = [image CGImage];
    CGDataProviderRef jpegProvider = CGImageGetDataProvider(cgJpegImage);

    CGImageRef cgBitmapImage = CGImageCreateWithJPEGDataProvider(jpegProvider, nil, NO, kCGRenderingIntentRelativeColorimetric);
    CGDataProviderRef bitmapProvider = CGImageGetDataProvider(cgBitmapImage);

    CFDataRef bitmapData = CGDataProviderCopyData(bitmapProvider);
    UInt8* data = (UInt8*)CFDataGetBytePtr(bitmapData);

    // other code to make sepia effect
}

你不能像普通RGB那样使用JPEG编码的图像。因此,只需先使用CGImageCreateWithJPEGDataProvider对其进行解码。

Paulo 10 年前

我怀疑您正在处理非RGBA格式的数据。。。。JPG没有Alpha频道。我建议您考虑使用核心图像过滤器,而不是处理复杂的数据,我已经将它们与jpg和PNG一起使用,没有任何问题。

有多种核心图像过滤器,其中一种用于Sepia,另一种用于灰度/黑白。这里是Sepia的代码:

-(UIImage*)makeSepiaScale:(UIImage*)input_image output:(UIImage *)output
{

 CIImage *cimage = [[CIImage alloc] initWithImage:input_image];  
CIFilter *myFilter = [CIFilter filterWithName:@"CISepiaTone"];

[myFilter setDefaults];
[myFilter setValue:cimage forKey:@"inputImage"];
[myFilter setValue:[NSNumber numberWithFloat:0.8f] forKey:@"inputIntensity"];

CIImage *image = [myFilter outputImage];
CIContext *context = [CIContext contextWithOptions:nil];
CGImageRef cgImage = [context createCGImage:image fromRect:image.extent];
output = [UIImage imageWithCGImage:cgImage];  
CGImageRelease(cgImage);
return (output);}

PS CoreImage上的苹果文档很好,我建议您仔细阅读。