iOS - 合并两个不同大小的图像

Question

我遇到以下问题：由于合并，我必须合并两个图像A和B以创建新图像C. 我已经知道如何合并两个图像但在这种情况下我的目标有点不同 我想图像A将是图像B的背景。
例如，如果图像A尺寸为500x500且图像B尺寸为460x460，我希望图像C（合并的图像结果）为500x500，图像B（460x460）位于其中心。

提前感谢您的任何帮助或建议

Answer 1

这是我在我的应用中所做的，但没有使用UIImageView：

UIImage *bottomImage = [UIImage imageNamed:@"bottom.png"]; //background image
UIImage *image       = [UIImage imageNamed:@"top.png"]; //foreground image

CGSize newSize = CGSizeMake(width, height);
UIGraphicsBeginImageContext( newSize );

// Use existing opacity as is
[bottomImage drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];

// Apply supplied opacity if applicable
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height) blendMode:kCGBlendModeNormal alpha:0.8];

UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

如果图像已经具有不透明度，则无需设置它（如在bottomImage中），否则可以设置它（与图像一样）。

创建此UIImage后，您可以将其嵌入UIImageView

更新：感谢Ahmet AkkoK - 对于Swift（2.2）用户，混合模式宏已经改变。 CGBlendMode .kCGBlendModeNormal替换为CGBlendMode.Normal

Answer 2

嘿，我有多个图像添加相同的背景与不同的前景 这是我的代码

UIImage *bottomImage = [UIImage imageNamed:@"photo 2.JPG"]; //background image
UIImage *image       = [UIImage imageNamed:@"photo 3.JPG"]; //foreground image
UIImage *image1      = [UIImage imageNamed:@"photo 4.JPG"]; //foreground image
UIImage *image2      = [UIImage imageNamed:@"photo 5.JPG"]; //foreground image

CGSize newSize = CGSizeMake(320, 480);
UIGraphicsBeginImageContext( newSize );

// Use existing opacity as is
[bottomImage drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];

// Apply supplied opacity if applicable
[image drawInRect:CGRectMake(0,0,newSize.width,newSize.height) blendMode:kCGBlendModeNormal alpha:0.4];
[image1 drawInRect:CGRectMake(0,0,newSize.width,newSize.height) blendMode:kCGBlendModeNormal alpha:0.3];
[image2 drawInRect:CGRectMake(0,0,newSize.width,newSize.height) blendMode:kCGBlendModeNormal alpha:0.2];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

resultView = [[UIImageView alloc] initWithImage:newImage];
resultView.frame = CGRectMake(0, 0,320,460);
[self.view addSubview:resultView];

Answer 3

Swift版本

复制/粘贴到游乐场

var bottomImage:UIImage = UIImage(named:"avatar_4.png") //background image

var imageTop:UIImage  = UIImage(named:"group_4.png")    //top image

var newSize = CGSizeMake(bottomImage.size.width, bottomImage.size.height)
UIGraphicsBeginImageContext( newSize )

bottomImage.drawInRect(CGRectMake(0,0,newSize.width,newSize.height))

// decrease top image to 36x36 
imageTop.drawInRect(CGRectMake(18,18,36,36), blendMode:kCGBlendModeNormal, alpha:1.0)

var newImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()
var imageData = UIImagePNGRepresentation(newImage)

---

从操场上加载图片：

• 打开playground文件并在其中创建文件夹Resources
• 将图像复制到此文件夹

Answer 4

为那些想要使用Srikar Appal答案的人做了快速粘贴功能。 （如果背景和前景图像的大小不同）

- (UIImage *) mergeImages:(NSString *)bgImageFileName foreGround:(NSString *)fgImageFileName  {
    UIImage *bottomImage = [UIImage imageNamed:bgImageFileName]; //background image
    UIImage *image       = [UIImage imageNamed:fgImageFileName]; //foreground image

    CGSize newSize = CGSizeMake(bottomImage.size.width, bottomImage.size.height);
    UIGraphicsBeginImageContext(newSize);

    // Use existing opacity as is
    [bottomImage drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];

    // Apply supplied opacity if applicable
    // Change xPos, yPos if applicable
    [image drawInRect:CGRectMake(11,11,image.size.width,image.size.height) blendMode:kCGBlendModeNormal alpha:1.0];

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();
    return newImage;
}

Answer 5

在Swift中

：

let bottomImage = UIImage(named: "Bottom_Image.png")
    let frontImage = UIImage (named: "Front_Image.png")
    let size = CGSize(width: 67, height: 55)
    UIGraphicsBeginImageContext(size)
    let areaSize = CGRect(x: 0, y: 0, width: size.width, height: size.height)
    let frontImageSize = CGRect(x: 14, y: 3, width: 40, height: 40)
    bottomImage!.drawInRect(areaSize, blendMode: CGBlendMode.Normal, alpha:  1.0)
    frontImage!.drawInRect(frontImageSize, blendMode: CGBlendMode.Normal, alpha: 1.0)

    let newImage:UIImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

Answer 6

感谢@Srikar Appal for iOS soultion。

对于在OS X中寻找合并的任何人：

- (NSImage *) mergeImages:(NSString *)bgImageFileName foreGround:(NSString *)fgImageFileName {
    NSImage *bottomImage = [NSImage imageNamed:bgImageFileName];
    NSImage *overlayedImage = [NSImage imageNamed:fgImageFileName];

    NSSize newSize = NSMakeSize(bottomImage.size.width, bottomImage.size.height);
    NSSize overlaySize = NSMakeSize(newSize.width/2, newSize.height/2); //change the size according to your requirements

    NSImage *newImage = [[NSImage alloc] initWithSize:newSize];

    [newImage lockFocus];

    [bottomImage drawInRect:NSMakeRect(0, 0, newSize.width, newSize.height)];
    [overlayedImage drawInRect:NSMakeRect(newSize.width-overlaySize.width, 0, overlaySize.width, overlaySize.height)]; //set the position as required

    [newImage unlockFocus];

    return newImage;
}

Answer 7

您可以使用另一个技巧，如下所述：

1. 将第一张图片添加到imageView。
2. 将第二张图片添加到另一张imageView。
3. 在单个主imageView中添加上述imageViews并按imageView属性访问合并图像： mainImageView.image

看看下面的代码：

    CGRect rect= investmentDetailTblView.frame;
    int rows = investmentDetailArray.count;

    CGFloat heightFinal = 5;
    CGRect frame1;

    for (int i=0; i<rows; i++)
    {
         frame1 = [investmentDetailTblView rectForRowAtIndexPath:[NSIndexPath indexPathForRow:i inSection:0]];
        CGFloat height = frame1.size.height;

        heightFinal = heightFinal + height;
    }
    rect.size.height = heightFinal;

    investmentDetailTblView.frame=rect;

    UIImageView *imageViewTable = [[UIImageView alloc] init];

    [imageViewTable setFrame:CGRectMake(0, 0, frame1.size.width, heightFinal)];


    [investmentDetailTblView reloadData];

    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)])
        UIGraphicsBeginImageContextWithOptions(investmentDetailTblView.bounds.size, NO, [UIScreen mainScreen].scale);
    else
        UIGraphicsBeginImageContext(investmentDetailTblView.bounds.size);

    [investmentDetailTblView.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    imageViewTable.image = image; //Adding the table image to the image view.


    CGRect frame=CGRectMake(0, heightFinal+5, investmentDetailTblView.frame.size.width, 20) ;
    UIView *footerView=[DataStore kkrLogoView];

    footerView.frame=frame;

    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)])
        UIGraphicsBeginImageContextWithOptions(footerView.frame.size, NO, [UIScreen mainScreen].scale);
    else
        UIGraphicsBeginImageContext(footerView.frame.size);

    [footerView.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *kkrLogoImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    UIImageView *imageViewFooter = [[UIImageView alloc] init];
    [imageViewFooter setFrame:CGRectMake(0, heightFinal, footerView.frame.size.width, footerView.frame.size.height)];
    imageViewFooter.image = kkrLogoImage; //Adding the footer image to the image view.


    UIImageView *mainImageView = [[UIImageView alloc] init];
    [mainImageView setFrame:CGRectMake(0, 0, frame1.size.width, (heightFinal+footerView.frame.size.height))];

    [mainImageView addSubview:imageViewTable];
    [mainImageView addSubview:imageViewFooter];

    if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)])
        UIGraphicsBeginImageContextWithOptions(mainImageView.frame.size, NO, [UIScreen mainScreen].scale);
    else
        UIGraphicsBeginImageContext(mainImageView.frame.size);

    [mainImageView.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();