我是 MonoTouch 的新手,我最近一直在将代码从标准 C# 转换为符合 MonoTouch 的代码,以便可以在 iPhone 应用程序中使用它。我已经设法转换了代码,但是我遇到了这个用于返回位图上下文的方法的问题:
private CGBitmapContext ExtractWriteableBitmap( RGBPaletteRecord rgbPalette, double dpi, ChartIndexFile indexFile, RasterChartFile chartFile )
{
CGBitmapContext bitmapImage = null;
TileRecord tile;
// calc the number of tiles in each plane
int tileCountX = indexFile.TileIndexRecords.Max(ti => ti.X);
int tileCountY = indexFile.TileIndexRecords.Max(ti => ti.Y);
// create the big picture
int pixelWidth = (tileCountX + 1) * TileRecord.PixelWidth;
int pixelHeight = (tileCountY + 1) * TileRecord.PixelHight;
int intDPI = Convert.ToInt32(dpi);
int bytesPerRow = (int)TileRecord.PixelWidth * 4; // note that bytes per row should
//be based on width, not height.
CGColorSpace colorSpace = CGColorSpace.CreateDeviceRGB();
CGImageAlphaInfo info = CGImageAlphaInfo.NoneSkipFirst;
// create the big picture
bitmapImage = new CGBitmapContext(System.IntPtr.Zero, pixelWidth, pixelHeight, intDPI, intDPI, colorSpace, info);
byte[] sourceArray;
RectangleF sourceRect;
//copy the tiles into the big picture
int index = 0;
foreach (TileIndexRecord tileIndexRecord in indexFile.TileIndexRecords)
{
// get the tile record
tile = chartFile.TileRecords[index];
// extract the byte array for the given palette
sourceArray = tile.GetBytes(rgbPalette);
GCHandle pinnedArray = GCHandle.Alloc(sourceArray, GCHandleType.Pinned);
IntPtr pointer = pinnedArray.AddrOfPinnedObject();
//do your stuff
//pinnedArray.Free();
CGImage image = new CGImage(pointer);
sourceRect = new RectangleF(0, 0, TileRecord.PixelWidth, TileRecord.PixelHight);
bitmapImage.DrawImage(new RectangleF(0,0,128,128),image);
// copy the tile image into the big picture
//bitmapImage.WritePixels(sourceRect, sourceArray, TileRecord.Stride, (tileIndexRecord.X * TileRecord.PixelWidth), (tileIndexRecord.Y * TileRecord.PixelHight));
// increment the index
index++;
}
return bitmapImage;
}
这是堆栈跟踪:
System.Exception: Invalid handle
at MonoTouch.CoreGraphics.CGContext..ctor (IntPtr handle, Boolean owns) [0x00022] in /Developer/MonoTouch/Source/monotouch/src/shared/CoreGraphics/CGContext.cs:136
at MonoTouch.CoreGraphics.CGBitmapContext..ctor (IntPtr data, Int32 width, Int32 height, Int32 bitsPerComponent, Int32 bytesPerRow, MonoTouch.CoreGraphics.CGColorSpace colorSpace, CGImageAlphaInfo bitmapInfo) [0x00000] in <filename unknown>:0
at Jargoon.Data.Arcs.Loader.ExtractWriteableBitmap (Jargoon.Data.Arcs.Records.RGBPaletteRecord rgbPalette, Double dpi, Jargoon.Data.Arcs.Raschts.ChartIndexFile indexFile, Jargoon.Data.Arcs.Raschts.RasterChartFile chartFile) [0x00079] in /Users/jacknutkins/Desktop/Jargoon/ARCSViewer/ARCSViewer/Loader.cs:569
at Jargoon.Data.Arcs.Loader.GetHiResImage (Jargoon.Data.Arcs.Records.RGBPaletteRecord rgbPalette) [0x00000] in /Users/jacknutkins/Desktop/Jargoon/ARCSViewer/ARCSViewer/Loader.cs:361
at ARCSViewer.ARCSViewerViewController.ViewDidLoad () [0x0001c] in /Users/jacknutkins/Desktop/Jargoon/ARCSViewer/ARCSViewer/ARCSViewerViewController.cs:37
at (wrapper managed-to-native) MonoTouch.UIKit.UIApplication:UIApplicationMain (int,string[],intptr,intptr)
at MonoTouch.UIKit.UIApplication.Main (System.String[] args, System.String principalClassName, System.String delegateClassName) [0x00042] in /Developer/MonoTouch/Source/monotouch/src/UIKit/UIApplication.cs:29
at ARCSViewer.Application.Main (System.String[] args) [0x00000] in /Users/jacknutkins/Desktop/Jargoon/ARCSViewer/ARCSViewer/Main.cs:17
错误发生在以下行:
// create the big picture
bitmapImage = new CGBitmapContext(System.IntPtr.Zero, pixelWidth, pixelHeight, intDPI, intDPI, colorSpace, info);
我对 MonoTouch 很陌生,所以如果它非常明显,请尝试忍受我,但有人可以解释发生了什么吗?