Iphone 使用分割器将图像分成两部分

我正在开发一个应用程序，我需要用红线将图像分成两部分

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问题1.

如何在图像上画红线

问题2.

如何使用红线将图像分割为两部分？（红线位置不固定。用户可以将位置移动到任意位置）

问题3.

我怎样才能得到线的当前位置，我怎样才能使用那个位置来分割图像

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提前感谢您的惠顾，您可以试试这个

UIImage *image = [UIImage imageNamed:@"yourImage.png"];
CGImageRef tmpImgRef = image.CGImage;
CGImageRef topImgRef = CGImageCreateWithImageInRect(tmpImgRef, CGRectMake(0, 0, image.size.width, image.size.height / 2.0));
UIImage *topImage = [UIImage imageWithCGImage:topImgRef];
CGImageRelease(topImgRef);

CGImageRef bottomImgRef = CGImageCreateWithImageInRect(tmpImgRef, CGRectMake(0, image.size.height / 2.0,  image.size.width, image.size.height / 2.0));
UIImage *bottomImage = [UIImage imageWithCGImage:bottomImgRef];
CGImageRelease(bottomImgRef);

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希望这能对你有所帮助，：）

如果你想画一条线，你可以使用一个红色背景的UIView，将高度设置为图像的大小，宽度设置为5像素左右

    UIView *imageToSplit; //the image im trying to split using a red bar
    CGRect i = imageToSplit.frame;
    int x = i.origin.x + i.size.width/2;
    int y = i.origin.y;
    int width = 5;
    int height = i.size.height;
    UIView *bar = [[[UIView alloc] initWithFrame:CGRectMake(x, y, width, height)] autorelease];
    bar.backgroundColor = [UIColor redColor];
    [self.view addSubview:bar];

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我将以与科雷所建议的相同的方式来处理这一问题：

1） 我假设您上面的图像/视图将由视图控制器管理，从现在起我将其称为ImageSeparator或ViewController

在ImageSeparatorViewController内部，在-（void）viewDidLoad{}方法中插入koray的代码。确保将imageToSplit变量更改为UIImageView而不是普通UIView

2） 接下来，我假设您知道如何检测用户手势。您将检测到这些手势，并确定用户是否已选择视图（即koray代码中的栏）。一旦确定用户是否选择了栏，只需使用触摸位置更新其原点的X位置

CGRect barFrame = bar.frame; 
barFrame.origin.x = *X location of the users touch*
bar.frame = barFrame;

3） 对于裁剪，我不会使用，它不会执行您需要执行的操作。

请尝试以下尺寸：

标题：

@interface UIImage (ImageDivider)

- (UIImage*)imageWithDividerAt:(CGFloat)position width:(CGFloat)width color:(UIColor*)color;
- (UIImage*)imageWithDividerAt:(CGFloat)position patternImage:(UIImage*)patternImage;
- (NSArray*)imagesBySlicingAt:(CGFloat)position;

@end

@implementation UIImage (ImageDivider)

- (UIImage*)imageWithDividerAt:(CGFloat)position patternImage:(UIImage*)patternImage
{
    //pattern image
    UIColor *patternColor = [UIColor colorWithPatternImage:patternImage];
    CGFloat width = patternImage.size.width;

    //set up context
    UIGraphicsBeginImageContext(self.size);
    CGContextRef context = UIGraphicsGetCurrentContext();

    //draw the existing image into the context
    [self drawAtPoint:CGPointZero];

    //set the fill color from the pattern image color
    CGContextSetFillColorWithColor(context, patternColor.CGColor);

    //this is your divider's area
    CGRect dividerRect = CGRectMake(position - (width / 2.0f), 0, width, self.size.height);

    //the joy of image color patterns being based on 0,0 origin! must set phase
    CGContextSetPatternPhase(context, CGSizeMake(dividerRect.origin.x, 0));

    //fill the divider rect with the repeating pattern from the image
    CGContextFillRect(context, dividerRect);

    //get your new image and viola!
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

- (UIImage*)imageWithDividerAt:(CGFloat)position width:(CGFloat)width color:(UIColor *)color
{
    //set up context
    UIGraphicsBeginImageContext(self.size);
    CGContextRef context = UIGraphicsGetCurrentContext();

    //draw the existing image into the context
    [self drawAtPoint:CGPointZero];

    //set the fill color for your divider
    CGContextSetFillColorWithColor(context, color.CGColor);

    //this is your divider's area
    CGRect dividerRect = CGRectMake(position - (width / 2.0f), 0, width, self.size.height);

    //fill the divider's rect with the provided color
    CGContextFillRect(context, dividerRect);

    //get your new image and viola!
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

- (NSArray*)imagesBySlicingAt:(CGFloat)position
{
    NSMutableArray *slices = [NSMutableArray array];

    //first image
    {
        //context!
        UIGraphicsBeginImageContext(CGSizeMake(position, self.size.height));

        //draw the existing image into the context
        [self drawAtPoint:CGPointZero];

        //get your new image and viola!
        [slices addObject:UIGraphicsGetImageFromCurrentImageContext()];
        UIGraphicsEndImageContext();
    }

    //second
    {
        //context!
        UIGraphicsBeginImageContext(CGSizeMake(self.size.width - position, self.size.height));

        //draw the existing image into the context
        [self drawAtPoint:CGPointMake(-position, 0)];

        //get your new image and viola!
        [slices addObject:UIGraphicsGetImageFromCurrentImageContext()];
        UIGraphicsEndImageContext();
    }
    return slices;
}

实施：

@interface UIImage (ImageDivider)

- (UIImage*)imageWithDividerAt:(CGFloat)position width:(CGFloat)width color:(UIColor*)color;
- (UIImage*)imageWithDividerAt:(CGFloat)position patternImage:(UIImage*)patternImage;
- (NSArray*)imagesBySlicingAt:(CGFloat)position;

@end

@implementation UIImage (ImageDivider)

- (UIImage*)imageWithDividerAt:(CGFloat)position patternImage:(UIImage*)patternImage
{
    //pattern image
    UIColor *patternColor = [UIColor colorWithPatternImage:patternImage];
    CGFloat width = patternImage.size.width;

    //set up context
    UIGraphicsBeginImageContext(self.size);
    CGContextRef context = UIGraphicsGetCurrentContext();

    //draw the existing image into the context
    [self drawAtPoint:CGPointZero];

    //set the fill color from the pattern image color
    CGContextSetFillColorWithColor(context, patternColor.CGColor);

    //this is your divider's area
    CGRect dividerRect = CGRectMake(position - (width / 2.0f), 0, width, self.size.height);

    //the joy of image color patterns being based on 0,0 origin! must set phase
    CGContextSetPatternPhase(context, CGSizeMake(dividerRect.origin.x, 0));

    //fill the divider rect with the repeating pattern from the image
    CGContextFillRect(context, dividerRect);

    //get your new image and viola!
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

- (UIImage*)imageWithDividerAt:(CGFloat)position width:(CGFloat)width color:(UIColor *)color
{
    //set up context
    UIGraphicsBeginImageContext(self.size);
    CGContextRef context = UIGraphicsGetCurrentContext();

    //draw the existing image into the context
    [self drawAtPoint:CGPointZero];

    //set the fill color for your divider
    CGContextSetFillColorWithColor(context, color.CGColor);

    //this is your divider's area
    CGRect dividerRect = CGRectMake(position - (width / 2.0f), 0, width, self.size.height);

    //fill the divider's rect with the provided color
    CGContextFillRect(context, dividerRect);

    //get your new image and viola!
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

- (NSArray*)imagesBySlicingAt:(CGFloat)position
{
    NSMutableArray *slices = [NSMutableArray array];

    //first image
    {
        //context!
        UIGraphicsBeginImageContext(CGSizeMake(position, self.size.height));

        //draw the existing image into the context
        [self drawAtPoint:CGPointZero];

        //get your new image and viola!
        [slices addObject:UIGraphicsGetImageFromCurrentImageContext()];
        UIGraphicsEndImageContext();
    }

    //second
    {
        //context!
        UIGraphicsBeginImageContext(CGSizeMake(self.size.width - position, self.size.height));

        //draw the existing image into the context
        [self drawAtPoint:CGPointMake(-position, 0)];

        //get your new image and viola!
        [slices addObject:UIGraphicsGetImageFromCurrentImageContext()];
        UIGraphicsEndImageContext();
    }
    return slices;
}

这个概念很简单——你想要一个画有分割线的图像。您可以只覆盖一个视图，或覆盖

drawRect:

，或任何数量的解决方案。我宁愿给你这个类别。它只需使用一些快速核心图形调用，在指定位置生成具有所需分割线的图像，无论是图案图像还是颜色。如果您还希望支持水平分隔符，那么将其修改为水平分隔符相当简单奖励：您可以使用平铺图像作为分割线

现在回答您的主要问题。使用这个类别是很自然的——只需在源背景上调用两个方法中的一个，用分割器生成一个，然后应用该图像而不是原始源图像

现在，第二个问题很简单-移动分割器后，根据新的分割器位置重新生成图像。这实际上是一种效率相对较低的方法，但对于您的目的来说，这应该足够轻，并且仅在移动分隔器时是一个问题。过早优化也是一种罪恶

第三个问题也很简单-调用

imagesBySlicingAt:

-它将返回一个由两个图像组成的数组，这两个图像是通过在提供的位置对图像进行切片生成的。随心所欲地使用它们

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此代码已通过功能测试。我强烈建议您随意使用它，不是出于任何实用目的，而是为了更好地理解所使用的机制，以便下次您能够回答问题

谢谢您的回答，但我已经使用了此代码，它工作得很好。如何在图像上添加红线，并使用红线分割图像。任何参考或想法。这可能对你有帮助。但是你必须处理它来管理你的跳线。我尝试了BFCropInterface和BJImageCropper，但是这两种方法都是裁剪图像而不是分割图像。这很好。这对我很有帮助。非常感谢。