調整大小WritableBitmap

Question

我已經創建了Gray16格式的WriteableBitmap。我想將此WriteableBitmap調整爲保留像素格式（Gray16）的已知維數。

是否有人在調整WriteableBitmap的大小。請幫幫我。

我也搜索了互聯網，發現http://writeablebitmapex.codeplex.com/但通過assebmly引用錯誤。

請幫幫我。

Answer 1

我寫了調整writableBitmap的函數。我已經發布的代碼在我的博客：

http://harshaprojects.wordpress.com/2010/08/30/resize-writable-bitmap-in-wpf/

希望這會有所幫助。

代碼：

using System; 
using System.Collections.Generic; 
using System.Linq; 
using System.Text; 
using System.Windows.Media; 
using System.Windows.Media.Imaging; 
using Microsoft.Win32; 
using System.IO; 
using System.Windows.Interop; 
namespace System.Windows.Media.Imaging 
{ 
public static class RewritableBitmap 
{ 
public static WriteableBitmap ResizeWritableBitmap(this WriteableBitmap wBitmap,int reqWidth, int reqHeight) 
{ 
int Stride = wBitmap.PixelWidth * ((wBitmap.Format.BitsPerPixel + 7)/8); 
int NumPixels = Stride * wBitmap.PixelHeight; 
ushort[] ArrayOfPixels = new ushort[NumPixels]; 


wBitmap.CopyPixels(ArrayOfPixels, Stride, 0); 

int OriWidth = (int) wBitmap.PixelWidth; 
int OriHeight = (int) wBitmap.PixelHeight; 

double nXFactor = (double)OriWidth/(double)reqWidth; 
double nYFactor = (double)OriHeight/(double)reqHeight; 

double fraction_x, fraction_y, one_minus_x, one_minus_y; 
int ceil_x, ceil_y, floor_x, floor_y; 

ushort pix1, pix2, pix3, pix4; 
int nStride = reqWidth * ((wBitmap.Format.BitsPerPixel + 7)/8); 
int nNumPixels = reqWidth * reqHeight; 
ushort[] newArrayOfPixels = new ushort[nNumPixels]; 
/*Core Part*/ 
      /* Code project article : 
Image Processing for Dummies with C# and GDI+ Part 2 - Convolution Filters By Christian Graus</a> 

      href=<a href="http://www.codeproject.com/KB/GDI-plus/csharpfilters.aspx"></a> 
      */ 
      for (int y = 0; y < reqHeight; y++) 
{ 
for (int x = 0; x < reqWidth; x++) 
{ 
// Setup 
floor_x = (int)Math.Floor(x * nXFactor); 
floor_y = (int)Math.Floor(y * nYFactor); 

ceil_x = floor_x + 1; 
if (ceil_x >= OriWidth) ceil_x = floor_x; 

ceil_y = floor_y + 1; 
if (ceil_y >= OriHeight) ceil_y = floor_y; 

fraction_x = x * nXFactor - floor_x; 
fraction_y = y * nYFactor - floor_y; 

one_minus_x = 1.0 - fraction_x; 
one_minus_y = 1.0 - fraction_y; 

pix1 = ArrayOfPixels[floor_x + floor_y * OriWidth]; 
pix2 = ArrayOfPixels[ceil_x + floor_y * OriWidth]; 
pix3 = ArrayOfPixels[floor_x + ceil_y * OriWidth]; 
pix4 = ArrayOfPixels[ceil_x + ceil_y * OriWidth]; 

ushort g1 = (ushort)(one_minus_x * pix1 + fraction_x * pix2); 
ushort g2 = (ushort)(one_minus_x * pix3 + fraction_x * pix4); 
ushort g = (ushort)(one_minus_y * (double)(g1) + fraction_y * (double)(g2)); 
newArrayOfPixels[y * reqWidth + x] = g; 
} 
} 
      /*End of Core Part*/ 
WriteableBitmap newWBitmap = new WriteableBitmap(reqWidth, reqHeight, 96, 96, PixelFormats.Gray16, null); 
Int32Rect Imagerect = new Int32Rect(0, 0, reqWidth, reqHeight); 
int newStride = reqWidth * ((PixelFormats.Gray16.BitsPerPixel + 7)/8); 
newWBitmap.WritePixels(Imagerect, newArrayOfPixels, newStride, 0); 
return newWBitmap; 
} 

} 
} 

Answer 2

您可以使用下面的函數來調整一個writableBitmap：

WriteableBitmap resize_image(WriteableBitmap img, double scale) 
{ 
    BitmapSource source = img; 

    var s = new ScaleTransform(scale, scale); 

    var res = new TransformedBitmap(img, s); 

    return convert_BitmapSource_to_WriteableBitmap(res); 
} 

WriteableBitmap convert_BitmapSource_to_WriteableBitmap(BitmapSource source) 
{ 
    // Calculate stride of source 
    int stride = source.PixelWidth * (source.Format.BitsPerPixel/8); 

    // Create data array to hold source pixel data 
    byte[] data = new byte[stride * source.PixelHeight]; 

    // Copy source image pixels to the data array 
    source.CopyPixels(data, stride, 0); 

    // Create WriteableBitmap to copy the pixel data to.  
    WriteableBitmap target = new WriteableBitmap(source.PixelWidth 
     , source.PixelHeight, source.DpiX, source.DpiY 
     , source.Format, null); 

    // Write the pixel data to the WriteableBitmap. 
    target.WritePixels(new Int32Rect(0, 0 
     , source.PixelWidth, source.PixelHeight) 
     , data, stride, 0); 

    return target; 
}