Question

如何在WP7上运行？

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

你还没有真正描述你想要什么，你只是想在屏幕上渲染图像更大/更小？或访问调整大小后的图像的像素值？

要将位图图像渲染为不同的大小/比例，您只需使用Image元素并根据需要设置其Width / Height。该框架将负责为您扩展它。
如果您需要获取缩放结果的像素值，请从（1）中描述的缩放图像构造WriteableBitmap。

Answer 2

这是我缩小从中间文件中选择的图像或用相机拍摄的图像，希望它有所帮助。它保持纵横比。

    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 3

这是我如何将图像尺寸减小到小于512 kb并将图像保存在隔离存储中，警告：只是Windows手机的初学者，所以请承担我编码的方式

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

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

在此方法中，我传递的是e.choosen流及其文件名

并在隔离存储中保存已调整大小的图像（图像大小减少小于512 kb），希望这对您有所帮助，

private void SaveToIsolatedStorage（Stream imageStream，string fileName） { 尝试 { 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);
        }
    }

希望这是helpFull

调整BitmapImage的大小wp7

3 个答案: