ios - 旋转注释自定义图像

已结束。此问题需要debugging details .它目前不接受答案。

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Best Answer-推荐答案

我遇到了同样的问题，我有一个似乎可行的解决方案。

您需要首先制作一个自定义注释，以保存您想要的数据(例如坐标、您的飞机航向)。当您遍历数据时，请确保您使用的是该自定义注释。例如

CustomAnnotation* annotation = [[CustomAnnotation alloc] init];
annotation.coordinates = ...
annotation.bearing = ...

然后在您的 viewForAnnotation 方法中，您可以通过执行类似的操作来获取该信息

if ([annotation isKindOfClass:[CustomAnnotation class]]) {
    CustomAnnotation* myAnn = (CustomAnnotation*)annotation;
    double bearing = myAnn.bearing; // or whatever it's called

    ...
}

希望这会有所帮助。

编辑:为了旋转图像，我在某处找到了以下代码片段。它有效，但它会使您的图像有点像素化。

@interface UIImage (RotationMethods)
- (UIImage *)imageRotatedByDegreesCGFloat)degrees;
@end

@implementation UIImage (RotationMethods)

static CGFloat DegreesToRadians(CGFloat degrees) {return degrees * M_PI / 180;};

- (UIImage *)imageRotatedByDegreesCGFloat)degrees
{
    // calculate the size of the rotated view's containing box for our drawing space
    UIView *rotatedViewBox = [[UIView alloc] initWithFrame:CGRectMake(0,0,self.size.width, self.size.height)];
    CGAffineTransform t = CGAffineTransformMakeRotation(DegreesToRadians(degrees));
    rotatedViewBox.transform = t;
    CGSize rotatedSize = rotatedViewBox.frame.size;

    // Create the bitmap context
    //UIGraphicsBeginImageContext(rotatedSize); // For iOS < 4.0
    UIGraphicsBeginImageContextWithOptions(rotatedSize, NO, 0.0);
    CGContextRef bitmap = UIGraphicsGetCurrentContext();

    // Move the origin to the middle of the image so we will rotate and scale around the center.
    CGContextTranslateCTM(bitmap, rotatedSize.width/2, rotatedSize.height/2);

    // Rotate the image context
    CGContextRotateCTM(bitmap, DegreesToRadians(degrees));

    // Now, draw the rotated/scaled image into the context
    CGContextScaleCTM(bitmap, 1.0, -1.0);
    CGContextDrawImage(bitmap, CGRectMake(-self.size.width / 2, -self.size.height / 2, self.size.width, self.size.height), [self CGImage]);

    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}

@end

将其粘贴在您的 .m 文件中，现在您可以在任何 UIImage 上执行 [someUIImage imageRotatedByDegrees:yourDegrees];

所以现在在您的 viewForAnnotation 方法中，您可以执行类似的操作

UIImage* image = [[UIImage imageNamed"yourImage.png"] imageRotatedByDegrees:degrees];
annView.image = image;

关于ios - 旋转注释自定义图像，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/30068060/