我一直在嘗試使用rococoa(java到osx cocoa api庫)來編寫一個簡單的屏幕截圖應用程序,並儘可能實際採取屏幕截圖,然後將其保存到文件。不幸的是,有一段時間,應用程序失敗,出現「無效的內存訪問...」錯誤。我假設這是由於垃圾收集的原因,因爲我沒有保持參考文件的存在。導致崩潰的行是: int [] data = pointer.getIntArray(0,bytesPerPlane/4);無效的內存訪問與洛可可位置
我真的沒有用Objective C編碼任何東西,剛開始用rococoa,所以我發現自己只是與此混淆。我已經複製下面的相關代碼,並非常感謝任何幫助!
public interface QuartzLibrary extends Library {
QuartzLibrary INSTANCE = (QuartzLibrary) Native.loadLibrary("Quartz", QuartzLibrary.class);
class CGPoint extends Structure {
public double x;
public double y;
}
class CGSize extends Structure {
public double width;
public double height;
}
class CGRect extends Structure implements Structure.ByValue {
public static class CGRectByValue extends CGRect { }
public CGPoint origin;
public CGSize size;
}
int kCGWindowListOptionIncludingWindow = (1 << 3);
int kCGWindowImageBoundsIgnoreFraming = (1 << 0);
ID CGWindowListCreateImage(CGRect screenBounds, int windowOption, int windowId, int imageOption);
}
public interface NSBitmapImageRep extends NSObject {
public static final _Class CLASS = Rococoa.createClass("NSBitmapImageRep", _Class.class);
public interface _Class extends NSClass {
NSBitmapImageRep alloc();
}
NSBitmapImageRep initWithCGImage(ID imageRef);
com.sun.jna.Pointer bitmapData();
NSSize size();
}
public class Screenshot {
public static void getScreenshot(int windowId) throws IOException {
QuartzLibrary.CGRect bounds = new QuartzLibrary.CGRect.CGRectByValue();
bounds.origin = new QuartzLibrary.CGPoint();
bounds.origin.x = 0;
bounds.origin.y = 0;
bounds.size = new QuartzLibrary.CGSize();
bounds.size.width = 0;
bounds.size.height = 0;
ID imageRef = QuartzLibrary.INSTANCE.CGWindowListCreateImage(bounds, QuartzLibrary.kCGWindowListOptionIncludingWindow, windowId, QuartzLibrary.kCGWindowImageBoundsIgnoreFraming);
NSBitmapImageRep imageRep = NSBitmapImageRep.CLASS.alloc();
imageRep = imageRep.initWithCGImage(imageRef);
NSSize size = imageRep.size();
com.sun.jna.Pointer pointer = imageRep.bitmapData();
int width = size.width.intValue();
int height = size.height.intValue();
BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB);
// The crash always happens when calling 'getIntArray' in the next line.
int[] data = pointer.getIntArray(0, bytesPerPlane/4);
int idx = 0;
for(int y = 0; y < height; y++)
for(int x = 0; x < width; x++)
image.setRGB(x, y, data[idx++]);
ImageIO.write(image, "png", new File("foo.png"));
}
}