C#合並BitMap圖像生成超大bitmap
當隻需要兩個圖像合並的時候,可以簡單的使用gdi+,把兩個圖像畫到一個畫佈上面實現合並bitmap.
當需要將許多bitmap合並時,由於bitmap類限制,長度或寬度太大時會報異常,前面這種方法就行不通瞭。
由於bitmapp屬於位圖格式,瞭解圖像格式後,發現,bitmap文件的第3-8位存儲瞭文件大小信息,第19-22位存儲瞭高度信息,第23-26位存儲瞭寬度信息。文件頭後面都是像素的argb,並無其它信息。於是,試想一下,如果把第二張圖像的像素argb放到第一張後面,並修改第一張的文件頭信息,是不是就可以實現文件合並瞭呢。事實證明:yes。
//設置文件頭裡面文件大小信息 public void SetBitmapFileSizeInfo(string filePath) { FileInfo fileInfo = new FileInfo(filePath); long le = fileInfo.Length; string hexSize = le.ToString("X").PadLeft(8, '0'); int size1 = Convert.ToInt32(hexSize.Substring(0, 2), 16); int size2 = Convert.ToInt32(hexSize.Substring(2, 2), 16); int size3 = Convert.ToInt32(hexSize.Substring(4, 2), 16); int size4 = Convert.ToInt32(hexSize.Substring(6, 2), 16); byte[] sizeBytes = new byte[] { (byte)size4, (byte)size3, (byte)size2, (byte)size1 }; using (FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Write)) { using (BinaryWriter r = new BinaryWriter(fs)) { r.Seek(2, 0); r.Write(sizeBytes, 0, sizeBytes.Length); } } }
設置文件頭裡面文件長度和寬度信息
public void SetBitmapSizeInfo(string filePath,int width=0,int height=0) { if (height != 0) { string hexHeight = height.ToString("X").PadLeft(8, '0'); int h1 = Convert.ToInt32(hexHeight.Substring(0, 2), 16); int h2 = Convert.ToInt32(hexHeight.Substring(2, 2), 16); int h3 = Convert.ToInt32(hexHeight.Substring(4, 2), 16); int h4 = Convert.ToInt32(hexHeight.Substring(6, 2), 16); byte[] sizeHeight = new byte[] { (byte)h4, (byte)h3, (byte)h2, (byte)h1 }; using (FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.ReadWrite)) { using (BinaryWriter r = new BinaryWriter(fs)) { r.Seek(22, 0);//高度保存位置 r.Write(sizeHeight, 0, sizeHeight.Length); } } } if (width != 0) { string hexWidth = height.ToString("X").PadLeft(8, '0'); int w1 = Convert.ToInt32(hexWidth.Substring(0, 2), 16); int w2 = Convert.ToInt32(hexWidth.Substring(2, 2), 16); int w3 = Convert.ToInt32(hexWidth.Substring(4, 2), 16); int w4 = Convert.ToInt32(hexWidth.Substring(6, 2), 16); byte[] sizeWidth = new byte[] { (byte)w4, (byte)w3, (byte)w2, (byte)w1 }; using (FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.ReadWrite)) { using (BinaryWriter r = new BinaryWriter(fs)) { r.Seek(18, 0);//高度保存位置 r.Write(sizeWidth, 0, sizeWidth.Length); } } } }
合並多個bitmap文件,並生成一個最終文件
private void CreateBitMap(string tempPath,string imagePath) { string[] files = Directory.GetFiles(tempPath, "*.png"); Bitmap bmp; int height=0; for (int i = files.Length-1; i >0; i--) { string fileName = files[i]; bmp = new Bitmap(fileName); if (i == files.Length - 1) { bmp.Save(imagePath, ImageFormat.Bmp); height += bmp.Height; bmp.Dispose(); continue; } else { byte[] bytes = GetImageRasterBytes(bmp, PixelFormat.Format32bppRgb); using (FileStream fs = new FileStream(imagePath, FileMode.Open, FileAccess.Write)) { fs.Seek(fs.Length, 0); fs.Write(bytes, 0, bytes.Length); } height += bmp.Height; bmp.Dispose(); } } SetBitmapFileSizeInfo(imagePath); SetBitmapSizeInfo(imagePath, height: height); //MessageBox.Show("合並成功"); } private static byte[] GetImageRasterBytes(Bitmap bmp, PixelFormat format) { Rectangle rect = new Rectangle(0, 0, bmp.Width, bmp.Height); byte[] bits = null; try { // Lock the managed memory BitmapData bmpdata = bmp.LockBits(rect, ImageLockMode.ReadWrite, format); // Declare an array to hold the bytes of the bitmap. bits = new byte[bmpdata.Stride * bmpdata.Height]; // Copy the values into the array. System.Runtime.InteropServices.Marshal.Copy(bmpdata.Scan0, bits, 0, bits.Length); // Release managed memory bmp.UnlockBits(bmpdata); } catch { return null; } return bits; }
到此這篇關於C#合並BitMap圖像生成超大bitmap的文章就介紹到這瞭,更多相關C#合並BitMap內容請搜索WalkonNet以前的文章或繼續瀏覽下面的相關文章希望大傢以後多多支持WalkonNet!
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