為什么在調整影像大小時結果不是我輸入的大小？

本例中的檔案型別為 jpg

private void beginOperationToolStripMenuItem_Click(object sender, EventArgs e)
        {
            if (files.Length > 0)
            {
                backgroundWorker1.RunWorkerAsync();
            }
        }

        private static Bitmap ResizeImage(String filename, int maxWidth, int maxHeight)
        {
            using (Image originalImage = Image.FromFile(filename))
            {
                //Caluate new Size
                int newWidth = originalImage.Width;
                int newHeight = originalImage.Height;
                double aspectRatio = (double)originalImage.Width / (double)originalImage.Height;
                if (aspectRatio <= 1 && originalImage.Width > maxWidth)
                {
                    newWidth = maxWidth;
                    newHeight = (int)Math.Round(newWidth / aspectRatio);
                }
                else if (aspectRatio > 1 && originalImage.Height > maxHeight)
                {
                    newHeight = maxHeight;
                    newWidth = (int)Math.Round(newHeight * aspectRatio);
                }
                if (newWidth >= 0 && newHeight >= 0)
                {
                    Bitmap newImage = new Bitmap(newWidth, newHeight);
                    using (Graphics g = Graphics.FromImage(newImage))
                    {
                        //--Quality Settings Adjust to fit your application
                        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBilinear;
                        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                        g.PixelOffsetMode = System.Drawing.Drawing2D.PixelOffsetMode.HighQuality;
                        g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
                        g.DrawImage(originalImage, 0, 0, newImage.Width, newImage.Height);
                        return newImage;
                    }
                }
                return null;
            }
        }

然后

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
        {
            try
            {
                BackgroundWorker worker = sender as BackgroundWorker;
                int counter = 0;
                int percentage = 0;
                foreach (string file in files)
                {                   
                    Bitmap bmp1 = new Bitmap(ResizeImage(file, 512, 512));
                    string resizedfilename = Path.Combine(directoryPath, Path.GetFileNameWithoutExtension(file)   "_resized.jpg");
                    bmp1.Save(resizedfilename);
                    bmp1.Dispose();
                    counter  ;
                    percentage = counter * 100 / files.Length;
                    worker.ReportProgress(percentage);
                }
            }
            catch(Exception err)
            {
                
            }
        }

硬碟上原圖jpg大小為寬536高589

硬碟上的resize圖片是寬512高536

為什么調整后的影像高度是 536 ？

為什么調整后的圖片在硬碟上的大小是600 KB，而原始圖片大小只有130 KB？

uj5u.com熱心網友回復：

我認為您的縱橫比小于和大于向后。如果影像是“橫向”（寬度 > 高度），則縱橫比將為正（因為您正在執行width/ height）。如果它是“縱向”，它將是負面的。但你有相反的方式。

標籤：C＃ winforms

上一篇：在excel程式中尋找搜索

下一篇：Blazor和Microsoft.AspNetCore.Identity需要電子郵件