2014/10/15 下午 10:05:00

iphone Programming Glossary: cgcontextdrawimage

Retrieving a pixel alpha value for a UIImage

http://stackoverflow.com/questions/1042830/retrieving-a-pixel-alpha-value-for-a-uiimage

How would I tint an image programatically on the iPhone?

http://stackoverflow.com/questions/1117211/how-would-i-tint-an-image-programatically-on-the-iphone

CGContextRef context UIGraphicsGetCurrentContext CGContextSaveGState context Draw picture first CGContextDrawImage context self.frame self.image.CGImage Blend mode could be any of CGBlendMode values. Now draw filled..

Resizing UIimages pulled from the Camera also ROTATES the UIimage?

http://stackoverflow.com/questions/1260249/resizing-uiimages-pulled-from-the-camera-also-rotates-the-uiimage

width height CGImageGetBitsPerComponent imageRef 4 width CGImageGetColorSpace imageRef alphaInfo CGContextDrawImage bitmap CGRectMake 0 0 width height imageRef CGImageRef ref CGBitmapContextCreateImage bitmap UIImage.. CGContextTranslateCTM bitmap targetWidth targetHeight CGContextRotateCTM bitmap radians 180. CGContextDrawImage bitmap CGRectMake 0 0 targetWidth targetHeight imageRef CGImageRef ref CGBitmapContextCreateImage bitmap..

Convert image to grayscale

http://stackoverflow.com/questions/1298867/convert-image-to-grayscale

colorSpace kCGImageAlphaPremultipliedLast kCGBitmapByteOrder32Big CGColorSpaceRelease colorSpace CGContextDrawImage context CGRectMake 0 0 width height image CGContextRelease context return rawData UIImage processImage.. context kCGInterpolationHigh CGContextSetShouldAntialias context NO CGContextDrawImage context CGRectMake 0 0 m_width m_height i CGImage CGContextRelease context CGColorSpaceRelease colorSpace..

How to Rotate a UIImage 90 degrees?

http://stackoverflow.com/questions/1315251/how-to-rotate-a-uiimage-90-degrees

CGContextRotateCTM bitmap radians 90 CGContextTranslateCTM bitmap 0 targetHeight CGContextDrawImage bitmap CGRectMake 0 0 targetWidth targetHeight imageRef CGImageRef ref CGBitmapContextCreateImage bitmap..

How to get the RGB values for a pixel on an image on the iphone

http://stackoverflow.com/questions/144250/how-to-get-the-rgb-values-for-a-pixel-on-an-image-on-the-iphone

raw image pixelData in the specified color space. CGRect rect 0 0 self.size.width self.size.height CGContextDrawImage context rect self.CGImage Now we can get a pointer to the image pixelData associated with the bitmap..

Rounded UIView using CALayers - only some corners - How?

http://stackoverflow.com/questions/2264083/rounded-uiview-using-calayers-only-some-corners-how

0 0 w h addRoundedRectToPath context rect 50 1 CGContextClosePath context CGContextClip context CGContextDrawImage context rect img.CGImage CGImageRef imageMasked CGBitmapContextCreateImage context CGContextRelease..

How do I export UIImage array as a movie?

http://stackoverflow.com/questions/3741323/how-do-i-export-uiimage-array-as-a-movie

kCGImageAlphaNoneSkipFirst NSParameterAssert context CGContextConcatCTM context frameTransform CGContextDrawImage context CGRectMake 0 0 CGImageGetWidth image CGImageGetHeight image image CGColorSpaceRelease rgbColorSpace..

Fast and Lean PDF Viewer for iPhone / iPad / iOs - tips and hints?

http://stackoverflow.com/questions/3889634/fast-and-lean-pdf-viewer-for-iphone-ipad-ios-tips-and-hints

imageSize.width 2 self.bounds.size.height imageSize.height 2 imageSize.width imageSize.height CGContextDrawImage context imageRect baseImage CGImage else @synchronized issue CGPDFPageRef pdfPage CGPDFDocumentGetPage..

iOS SDK - Programmatically generate a PDF file

http://stackoverflow.com/questions/4362734/ios-sdk-programmatically-generate-a-pdf-file

provider NULL true kCGRenderingIntentDefault CGDataProviderRelease provider CGContextDrawImage pdfContext CGRectMake 200 200 207 385 image CGImageRelease image End image code Adding some text on..

UIImagePickerController camera preview is portrait in landscape app

http://stackoverflow.com/questions/538041/uiimagepickercontroller-camera-preview-is-portrait-in-landscape-app

scaleRatio scaleRatio CGContextTranslateCTM context 0 height CGContextConcatCTM context transform CGContextDrawImage UIGraphicsGetCurrentContext CGRectMake 0 0 width height imgRef UIImage imageCopy UIGraphicsGetImageFromCurrentImageContext..

iOS UIImagePickerController result image orientation after upload

http://stackoverflow.com/questions/5427656/ios-uiimagepickercontroller-result-image-orientation-after-upload

case UIImageOrientationRight case UIImageOrientationRightMirrored Grr... CGContextDrawImage ctx CGRectMake 0 0 self.size.height self.size.width self.CGImage break default CGContextDrawImage ctx.. CGContextDrawImage ctx CGRectMake 0 0 self.size.height self.size.width self.CGImage break default CGContextDrawImage ctx CGRectMake 0 0 self.size.width self.size.height self.CGImage break And now we just create a new..

Retrieving a pixel alpha value for a UIImage

http://stackoverflow.com/questions/1042830/retrieving-a-pixel-alpha-value-for-a-uiimage

How would I tint an image programatically on the iPhone?

http://stackoverflow.com/questions/1117211/how-would-i-tint-an-image-programatically-on-the-iphone

blending mode something like this void drawRect CGRect area CGContextRef context UIGraphicsGetCurrentContext CGContextSaveGState context Draw picture first CGContextDrawImage context self.frame self.image.CGImage Blend mode could be any of CGBlendMode values. Now draw filled rectangle over top of image. CGContextSetBlendMode context..

Resizing UIimages pulled from the Camera also ROTATES the UIimage?

http://stackoverflow.com/questions/1260249/resizing-uiimages-pulled-from-the-camera-also-rotates-the-uiimage

CGContextRef bitmap CGBitmapContextCreate NULL width height CGImageGetBitsPerComponent imageRef 4 width CGImageGetColorSpace imageRef alphaInfo CGContextDrawImage bitmap CGRectMake 0 0 width height imageRef CGImageRef ref CGBitmapContextCreateImage bitmap UIImage result UIImage imageWithCGImage ref CGContextRelease bitmap.. else if sourceImage.imageOrientation UIImageOrientationDown CGContextTranslateCTM bitmap targetWidth targetHeight CGContextRotateCTM bitmap radians 180. CGContextDrawImage bitmap CGRectMake 0 0 targetWidth targetHeight imageRef CGImageRef ref CGBitmapContextCreateImage bitmap UIImage newImage UIImage imageWithCGImage ref CGContextRelease..

Convert image to grayscale

http://stackoverflow.com/questions/1298867/convert-image-to-grayscale

rawData width height bitsPerComponent bytesPerRow colorSpace kCGImageAlphaPremultipliedLast kCGBitmapByteOrder32Big CGColorSpaceRelease colorSpace CGContextDrawImage context CGRectMake 0 0 width height image CGContextRelease context return rawData UIImage processImage UIImage pImage DebugLog @ processing image unsigned char.. kCGBitmapByteOrder32Little kCGImageAlphaNoneSkipLast CGContextSetInterpolationQuality context kCGInterpolationHigh CGContextSetShouldAntialias context NO CGContextDrawImage context CGRectMake 0 0 m_width m_height i CGImage CGContextRelease context CGColorSpaceRelease colorSpace now convert to grayscale uint8_t m_imageData uint8_t malloc..

How to Rotate a UIImage 90 degrees?

http://stackoverflow.com/questions/1315251/how-to-rotate-a-uiimage-90-degrees

NOTHING else if sourceImage.imageOrientation UIImageOrientationUp CGContextRotateCTM bitmap radians 90 CGContextTranslateCTM bitmap 0 targetHeight CGContextDrawImage bitmap CGRectMake 0 0 targetWidth targetHeight imageRef CGImageRef ref CGBitmapContextCreateImage bitmap UIImage newImage UIImage imageWithCGImage ref CGContextRelease..

How to get the RGB values for a pixel on an image on the iphone

http://stackoverflow.com/questions/144250/how-to-get-the-rgb-values-for-a-pixel-on-an-image-on-the-iphone

for the context for rendering will then contain the raw image pixelData in the specified color space. CGRect rect 0 0 self.size.width self.size.height CGContextDrawImage context rect self.CGImage Now we can get a pointer to the image pixelData associated with the bitmap context. pixelData RGBAPixel CGBitmapContextGetData context..

Rounded UIView using CALayers - only some corners - How?

http://stackoverflow.com/questions/2264083/rounded-uiview-using-calayers-only-some-corners-how

CGContextBeginPath context CGRect rect CGRectMake 0 0 w h addRoundedRectToPath context rect 50 1 CGContextClosePath context CGContextClip context CGContextDrawImage context rect img.CGImage CGImageRef imageMasked CGBitmapContextCreateImage context CGContextRelease context CGColorSpaceRelease colorSpace img release return UIImage..

How do I export UIImage array as a movie?

http://stackoverflow.com/questions/3741323/how-do-i-export-uiimage-array-as-a-movie

frameSize.height 8 4 frameSize.width rgbColorSpace kCGImageAlphaNoneSkipFirst NSParameterAssert context CGContextConcatCTM context frameTransform CGContextDrawImage context CGRectMake 0 0 CGImageGetWidth image CGImageGetHeight image image CGColorSpaceRelease rgbColorSpace CGContextRelease context CVPixelBufferUnlockBaseAddress..

Fast and Lean PDF Viewer for iPhone / iPad / iOs - tips and hints?

http://stackoverflow.com/questions/3889634/fast-and-lean-pdf-viewer-for-iphone-ipad-ios-tips-and-hints

CGRect imageRect CGRectMake self.bounds.size.width imageSize.width 2 self.bounds.size.height imageSize.height 2 imageSize.width imageSize.height CGContextDrawImage context imageRect baseImage CGImage else @synchronized issue CGPDFPageRef pdfPage CGPDFDocumentGetPage issue.pdfDoc pageIndex 1 pdfToPageTransform CGPDFPageGetDrawingTransform..

iOS SDK - Programmatically generate a PDF file

http://stackoverflow.com/questions/4362734/ios-sdk-programmatically-generate-a-pdf-file

pictureURL CFRelease pictureURL image CGImageCreateWithPNGDataProvider provider NULL true kCGRenderingIntentDefault CGDataProviderRelease provider CGContextDrawImage pdfContext CGRectMake 200 200 207 385 image CGImageRelease image End image code Adding some text on top of the image we just added CGContextSelectFont pdfContext..

UIImagePickerController camera preview is portrait in landscape app

http://stackoverflow.com/questions/538041/uiimagepickercontroller-camera-preview-is-portrait-in-landscape-app

context height 0 else CGContextScaleCTM context scaleRatio scaleRatio CGContextTranslateCTM context 0 height CGContextConcatCTM context transform CGContextDrawImage UIGraphicsGetCurrentContext CGRectMake 0 0 width height imgRef UIImage imageCopy UIGraphicsGetImageFromCurrentImageContext UIGraphicsEndImageContext return imageCopy..

iOS UIImagePickerController result image orientation after upload

http://stackoverflow.com/questions/5427656/ios-uiimagepickercontroller-result-image-orientation-after-upload

case UIImageOrientationLeft case UIImageOrientationLeftMirrored case UIImageOrientationRight case UIImageOrientationRightMirrored Grr... CGContextDrawImage ctx CGRectMake 0 0 self.size.height self.size.width self.CGImage break default CGContextDrawImage ctx CGRectMake 0 0 self.size.width self.size.height self.CGImage.. case UIImageOrientationRightMirrored Grr... CGContextDrawImage ctx CGRectMake 0 0 self.size.height self.size.width self.CGImage break default CGContextDrawImage ctx CGRectMake 0 0 self.size.width self.size.height self.CGImage break And now we just create a new UIImage from the drawing context CGImageRef cgimg CGBitmapContextCreateImage..

Retrieving a pixel alpha value for a UIImage

http://stackoverflow.com/questions/1042830/retrieving-a-pixel-alpha-value-for-a-uiimage

How would I tint an image programatically on the iPhone?

http://stackoverflow.com/questions/1117211/how-would-i-tint-an-image-programatically-on-the-iphone

drawRect CGRect area CGContextRef context UIGraphicsGetCurrentContext CGContextSaveGState context Draw picture first CGContextDrawImage context self.frame self.image.CGImage Blend mode could be any of CGBlendMode values. Now draw filled rectangle over top..

Resizing UIimages pulled from the Camera also ROTATES the UIimage?

http://stackoverflow.com/questions/1260249/resizing-uiimages-pulled-from-the-camera-also-rotates-the-uiimage

NULL width height CGImageGetBitsPerComponent imageRef 4 width CGImageGetColorSpace imageRef alphaInfo CGContextDrawImage bitmap CGRectMake 0 0 width height imageRef CGImageRef ref CGBitmapContextCreateImage bitmap UIImage result UIImage imageWithCGImage.. UIImageOrientationDown CGContextTranslateCTM bitmap targetWidth targetHeight CGContextRotateCTM bitmap radians 180. CGContextDrawImage bitmap CGRectMake 0 0 targetWidth targetHeight imageRef CGImageRef ref CGBitmapContextCreateImage bitmap UIImage newImage..

Convert image to grayscale

http://stackoverflow.com/questions/1298867/convert-image-to-grayscale

bytesPerRow colorSpace kCGImageAlphaPremultipliedLast kCGBitmapByteOrder32Big CGColorSpaceRelease colorSpace CGContextDrawImage context CGRectMake 0 0 width height image CGContextRelease context return rawData UIImage processImage UIImage pImage DebugLog.. CGContextSetInterpolationQuality context kCGInterpolationHigh CGContextSetShouldAntialias context NO CGContextDrawImage context CGRectMake 0 0 m_width m_height i CGImage CGContextRelease context CGColorSpaceRelease colorSpace now convert to..

How to Rotate a UIImage 90 degrees?

http://stackoverflow.com/questions/1315251/how-to-rotate-a-uiimage-90-degrees

UIImageOrientationUp CGContextRotateCTM bitmap radians 90 CGContextTranslateCTM bitmap 0 targetHeight CGContextDrawImage bitmap CGRectMake 0 0 targetWidth targetHeight imageRef CGImageRef ref CGBitmapContextCreateImage bitmap UIImage newImage..

How to get the RGB values for a pixel on an image on the iphone

http://stackoverflow.com/questions/144250/how-to-get-the-rgb-values-for-a-pixel-on-an-image-on-the-iphone

then contain the raw image pixelData in the specified color space. CGRect rect 0 0 self.size.width self.size.height CGContextDrawImage context rect self.CGImage Now we can get a pointer to the image pixelData associated with the bitmap context. pixelData..

Rounded UIView using CALayers - only some corners - How?

http://stackoverflow.com/questions/2264083/rounded-uiview-using-calayers-only-some-corners-how

CGRect rect CGRectMake 0 0 w h addRoundedRectToPath context rect 50 1 CGContextClosePath context CGContextClip context CGContextDrawImage context rect img.CGImage CGImageRef imageMasked CGBitmapContextCreateImage context CGContextRelease context CGColorSpaceRelease..

How do I export UIImage array as a movie?

http://stackoverflow.com/questions/3741323/how-do-i-export-uiimage-array-as-a-movie

rgbColorSpace kCGImageAlphaNoneSkipFirst NSParameterAssert context CGContextConcatCTM context frameTransform CGContextDrawImage context CGRectMake 0 0 CGImageGetWidth image CGImageGetHeight image image CGColorSpaceRelease rgbColorSpace CGContextRelease..

Fast and Lean PDF Viewer for iPhone / iPad / iOs - tips and hints?

http://stackoverflow.com/questions/3889634/fast-and-lean-pdf-viewer-for-iphone-ipad-ios-tips-and-hints

self.bounds.size.width imageSize.width 2 self.bounds.size.height imageSize.height 2 imageSize.width imageSize.height CGContextDrawImage context imageRect baseImage CGImage else @synchronized issue CGPDFPageRef pdfPage CGPDFDocumentGetPage issue.pdfDoc pageIndex..

iOS SDK - Programmatically generate a PDF file

http://stackoverflow.com/questions/4362734/ios-sdk-programmatically-generate-a-pdf-file

image CGImageCreateWithPNGDataProvider provider NULL true kCGRenderingIntentDefault CGDataProviderRelease provider CGContextDrawImage pdfContext CGRectMake 200 200 207 385 image CGImageRelease image End image code Adding some text on top of the image we..

CGContextDrawImage draws image upside down when passed UIImage.CGImage

http://stackoverflow.com/questions/506622/cgcontextdrawimage-draws-image-upside-down-when-passed-uiimage-cgimage

draws image upside down when passed UIImage.CGImage Does anyone know why CGContextDrawImage would be drawing my image upside.. draws image upside down when passed UIImage.CGImage Does anyone know why CGContextDrawImage would be drawing my image upside down I am loading an image in from my application UIImage image UIImage imageNamed @ testImage.png.. UIImage image UIImage imageNamed @ testImage.png And then simply asking core graphics to draw it to my context CGContextDrawImage context CGRectMake 0 0 145 15 image.CGImage It renders in the right place and dimensions but the image is upside down. I..

UIImagePickerController camera preview is portrait in landscape app

http://stackoverflow.com/questions/538041/uiimagepickercontroller-camera-preview-is-portrait-in-landscape-app

context scaleRatio scaleRatio CGContextTranslateCTM context 0 height CGContextConcatCTM context transform CGContextDrawImage UIGraphicsGetCurrentContext CGRectMake 0 0 width height imgRef UIImage imageCopy UIGraphicsGetImageFromCurrentImageContext..

iOS UIImagePickerController result image orientation after upload

http://stackoverflow.com/questions/5427656/ios-uiimagepickercontroller-result-image-orientation-after-upload

case UIImageOrientationLeftMirrored case UIImageOrientationRight case UIImageOrientationRightMirrored Grr... CGContextDrawImage ctx CGRectMake 0 0 self.size.height self.size.width self.CGImage break default CGContextDrawImage ctx CGRectMake 0 0 self.size.width.. Grr... CGContextDrawImage ctx CGRectMake 0 0 self.size.height self.size.width self.CGImage break default CGContextDrawImage ctx CGRectMake 0 0 self.size.width self.size.height self.CGImage break And now we just create a new UIImage from the drawing..