How to resize a image in Objective - C to a smaller version of it? - iphone

Question

I have three images(.png format). I combine three images and create a speech bubble using drawInRect() for images and I specify the rectangle in which each single image is drawn.
I have created resizable images for each of the images using resizableImageWithCapInsets:UIEdgeInsetsMake.
My original images are quite big. and hence, when I add text which consists of only few characters, the speech bubble that is drawn looks bigger for the text.
Can anyone tell me how to shrink the images such a way that it surrounds the text appropriately.
My speech bubble has a top image and its original height is 17pixels and hence if I use drawInRect() with a rectangle below that height, part of the image gets clipped, so is the case with the bottom image.
Any help is appreciated. thank you.

Answer 1

We need to resize the image to our need, sample code snippet:
CGSize imageSize = CGSizeMake(320,480); // give any desired size you want
UIGraphicsBeginImageContext(itemSize);//Creates a bitmap-based graphics context
CGRect imageRect = CGRectMake(0.0, 0.0, imageSize.width, imageSize.height);//modify
[myimage drawInRect:imageRect];
myimage = UIGraphicsGetImageFromCurrentImageContext(); //returns new image
UIGraphicsEndImageContext();
Hope this helps.

Answer 2

- (UIImage*)imageByScalingAndCroppingForSize:(CGSize)targetSize
{
UIImage *sourceImage = self;
UIImage *newImage = nil;
CGSize imageSize = sourceImage.size;
CGFloat width = imageSize.width;
CGFloat height = imageSize.height;
CGFloat targetWidth = targetSize.width;
CGFloat targetHeight = targetSize.height;
CGFloat scaleFactor = 0.0;
CGFloat scaledWidth = targetWidth;
CGFloat scaledHeight = targetHeight;
CGPoint thumbnailPoint = CGPointMake(0.0,0.0);
if (CGSizeEqualToSize(imageSize, targetSize) == NO)
{
CGFloat widthFactor = targetWidth / width;
CGFloat heightFactor = targetHeight / height;
if (widthFactor > heightFactor)
scaleFactor = widthFactor; // scale to fit height
else
scaleFactor = heightFactor; // scale to fit width.
scaledWidth = width * scaleFactor;
scaledHeight = height * scaleFactor;
// center the image
if (widthFactor > heightFactor)
{
thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5;
}
else
if (widthFactor < heightFactor)
{
thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5;
}
}
UIGraphicsBeginImageContext(targetSize); // this will crop
CGRect thumbnailRect = CGRectZero;
thumbnailRect.origin = thumbnailPoint;
thumbnailRect.size.width = scaledWidth;
thumbnailRect.size.height = scaledHeight;
[sourceImage drawInRect:thumbnailRect];
newImage = UIGraphicsGetImageFromCurrentImageContext();
if(newImage == nil)
NSLog(#"could not scale image");
//pop the context to get back to the default
UIGraphicsEndImageContext();
return newImage;
}

Answer 3

try with this method:
-(UIImage *)imageWithImage:(UIImage *)imageToCompress scaledToSize:(CGSize)newSize {
UIGraphicsBeginImageContextWithOptions(newSize, NO, 0.0);
[imageToCompress drawInRect:CGRectMake(0, 0, newSize.width, newSize.height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return newImage;
}

Answer 4

Try this method for resizing image
-(UIImage *)resizeImage:(UIImage *)image width:(int)wdth height:(int)hght{
int w = image.size.width;
int h = image.size.height;
CGImageRef imageRef = [image CGImage];
int width, height;
int destWidth = wdth;
int destHeight = hght;
if(w > h){
width = destWidth;
height = h*destWidth/w;
}
else {
height = destHeight;
width = w*destHeight/h;
}
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef bitmap;
bitmap = CGBitmapContextCreate(NULL, width, height, 8, 4 * width, colorSpace, kCGImageAlphaPremultipliedFirst);
if (image.imageOrientation == UIImageOrientationLeft) {
CGContextRotateCTM (bitmap, M_PI/2);
CGContextTranslateCTM (bitmap, 0, -height);
} else if (image.imageOrientation == UIImageOrientationRight) {
CGContextRotateCTM (bitmap, -M_PI/2);
CGContextTranslateCTM (bitmap, -width, 0);
}
else if (image.imageOrientation == UIImageOrientationUp) {
} else if (image.imageOrientation == UIImageOrientationDown) {
CGContextTranslateCTM (bitmap, width,height);
CGContextRotateCTM (bitmap, -M_PI);
}
CGContextDrawImage(bitmap, CGRectMake(0, 0, width, height), imageRef);
CGImageRef ref = CGBitmapContextCreateImage(bitmap);
UIImage *result = [UIImage imageWithCGImage:ref];
CGContextRelease(bitmap);
CGImageRelease(ref);
return result;
}