Merge pull request #53 from dotnet-campus/t/lindexi/MediaConverter

修复图片计算尺寸越界

Author: walterlv

src/MediaConverters/MediaConverters.Lib/Imaging/Optimizations/ImageFileOptimization.cs

@@ -156,8 +156,20 @@ public static void LimitImageSize(Image<Rgba32> image, int maxPixelCount)
             return;
         }
 
-        var pixelWidth = (int) Math.Sqrt(maxPixelCount * image.Width / (double) image.Height);
-        var pixelHeight = (int) Math.Sqrt(maxPixelCount * image.Height / (double) image.Width);
+        // 提前计算 wh 和 hw 的值。而不是使用 maxPixelCount * Width / Height 的写法
+        // 避免大图的 maxPixelCount * Width 出现越界。如传入尺寸为
+        // maxImageWidth	507	
+        // maxImageHeight	1095
+        // maxPixelCount = maxImageWidth x maxImageHeight = 555165
+        // 图片的尺寸为 4000x4000
+        // 于是就有 maxPixelCount x Width = 555165 x 4000 = 2220660000 > int.MaxValue = 2147483647
+        // 出现越界错误
+
+        double wh = image.Width / (double) image.Height;
+        double hw = image.Height / (double) image.Width;
+
+        var pixelWidth = (int) Math.Sqrt(maxPixelCount * wh);
+        var pixelHeight = (int) Math.Sqrt(maxPixelCount * hw);
         image.Mutate(context => context.Resize(new Size(pixelWidth, pixelHeight), compand: true));
     }
 

src/MediaConverters/MediaConverters.Tests/Tool/MediaConverterTests.cs

@@ -361,4 +361,35 @@ private Options ToOptions(string fileName, ImageConvertContext imageConvertConte
             ConvertConfigurationFile = configFile,
         };
     }
+
+    /// <summary>
+    /// 这是一些自定义的测试，来源于用户反馈问题
+    /// 图片太大就不传了
+    /// </summary>
+    /// <returns></returns>
+#if DEBUG
+    [TestMethod]
+#endif
+    public async Task CustomTest()
+    {
+        var imageFile = @"C:\lindexi\Work\ImageTest\Test1\file.png";
+        var configFile = @"C:\lindexi\Work\ImageTest\Test1\file.json";
+
+        var testFolder = Path.Join(TestHelper.WorkingDirectory.FullName, Path.GetRandomFileName());
+        Directory.CreateDirectory(testFolder);
+        var workingFolder = Path.Join(testFolder, "Working");
+        var outputFile = Path.Join(testFolder, "Output.png");
+
+        var options = new Options()
+        {
+            WorkingFolder = workingFolder,
+            InputFile = imageFile,
+            OutputFile = outputFile,
+            ConvertConfigurationFile = configFile,
+        };
+
+        var result = await Program.RunAsync(options);
+        Assert.AreEqual(MediaConverterErrorCode.Success, result);
+        TestHelper.OpenFileInExplorer(new FileInfo(options.OutputFile));
+    }
 }