調整 BitmapImage wp7 的大小

Question

如何讓它在 WP7 上工作？

private static Bitmap ResizeBitmap(Bitmap sourceBMP, int width, int height)
{
    Bitmap result = new Bitmap(width, height);
    using (Graphics g = Graphics.FromImage(result))
        g.DrawImage(sourceBMP, 0, 0, width, height);
    return result;
}

Answer 1

這就是我縮小從媒體庫中選擇或用相機拍攝的圖像的方法，希望對您有所幫助。 它保持縱橫比。

    private void PhotoChooserTaskCompleted(object sender, PhotoResult e)
    {
        if (e.TaskResult != TaskResult.OK) return;

        var bmp = new BitmapImage();
        bmp.SetSource(e.ChosenPhoto);

        var scaledDownImage = AspectScale(bmp, 640, 480);

        MyImage.Source = scaledDownImage;
    }

    private BitmapImage AspectScale(BitmapImage img, int maxWidth, int maxHeigh)
    {
        double scaleRatio;

        if (img.PixelWidth > img.PixelHeight)
            scaleRatio = (maxWidth/(double) img.PixelWidth);
        else
            scaleRatio = (maxHeigh/(double) img.PixelHeight);

        var scaledWidth = img.PixelWidth * scaleRatio;
        var scaledHeight = img.PixelHeight * scaleRatio;

        using (var mem = new MemoryStream())
        {
            var wb = new WriteableBitmap(img);
            wb.SaveJpeg(mem, (int)scaledWidth, (int)scaledHeight, 0, 100);
            mem.Seek(0, SeekOrigin.Begin);
            var bn = new BitmapImage();
            bn.SetSource(mem);
            return bn;
        }
    }

Answer 2

這就是我如何將圖像大小減小到小於 512 kb 並將圖像保存在隔離存儲中，注意：只是 windows 手機的初學者，所以請遵守我的編碼方式

private void PhotoChooserTaskCompleted(object sender, PhotoResult e) { if (e.TaskResult.= TaskResult;OK) return;

  string Imgpath = "Rafiq.jpg";
                SaveToIsolatedStorage(e.ChosenPhoto, Imgpath);
}

在此方法中，我傳遞了 e.choosen 的 stream 及其文件名

並在獨立存儲中保存調整大小的圖像（圖像大小減少小於 512 kb），希望這對您有所幫助，

私人無效SaveToIsolatedStorage（流圖像流，字符串文件名）{嘗試{使用（IsolatedStorageFile myIsolatedStorage=IsolatedStorageFile.GetUserStoreForApplication（））{

                if (myIsolatedStorage.FileExists(fileName))
                {
                    myIsolatedStorage.DeleteFile(fileName);
                }
                IsolatedStorageFileStream fileStream = myIsolatedStorage.CreateFile(fileName);

                BitmapImage bitmap = new BitmapImage();
                bitmap.SetSource(imageStream);
                MessageBox.Show("ImageStream :"+ imageStream.Length.ToString());
                WriteableBitmap wb = new WriteableBitmap(bitmap);

         // reeducing less than 524288 byte array

                long compImageSize = 524288;
                long originalsize =  wb.ToByteArray().Length;

                if ((Convert.ToInt32(originalsize)) > compImageSize)
                {
                    WriteableBitmap wBitmap = new WriteableBitmap(bitmap);
                    int height = wBitmap.PixelHeight;
                    int width = wBitmap.PixelWidth;



                    while ((Convert.ToInt32(originalsize)) > compImageSize)
                    {
                        //  wb.Resize(Convert.ToInt32( wb.PixelWidth / 2), Convert.ToInt32(wb.PixelHeight / 2), WriteableBitmapExtensions.Interpolation.Bilinear);

                        // data = ChangeDimension(bitmap, Convert.ToInt32(bitmap.PixelWidth / 2), Convert.ToInt32(bitmap.PixelHeight / 2));

                        using (MemoryStream stream = new MemoryStream())
                        {
                            height = Convert.ToInt32(wBitmap.PixelHeight / 2);
                            width = Convert.ToInt32(wBitmap.PixelWidth / 2);

                            wBitmap.SaveJpeg(stream, width, height, 0, 100);
                            stream.Seek(0, SeekOrigin.Begin);
                            wBitmap.SetSource(stream);

                        }

                        originalsize = wBitmap.ToByteArray().Length;

                    }

                    wb.SaveJpeg(fileStream, width, height, 0, 100);
                }
                else
                {
                    wb.SaveJpeg(fileStream, wb.PixelWidth, wb.PixelHeight, 0, 100);
                }

                fileStream.Close();          


            }
        }
        catch (Exception ex)
        {
            MessageBox.Show(ex.Message);
        }
    }

希望這是有幫助的

Answer 3

您還沒有真正准確地描述您想要什么，您只是想在屏幕上將圖像渲染得更大/更小嗎？ 或訪問調整大小圖像的像素值？

1. 要將 bitmap 圖像渲染為不同的大小/比例，您只需使用Image元素並根據需要設置其Width / Height 。 該框架將負責為您擴展它。
2. 如果需要獲取縮放結果的像素值，請從（1）中描述的縮放圖像構造一個WriteableBitmap 。