Aspose.Imaging for .NET一種高級圖像處理控件，允許開發人員創建，編輯，繪制或轉換圖像。圖像導出和轉換是API核心功能之一，它允許在不安裝Photoshop應用程序或任何其他圖像編輯器的情況下保存為AdobePhotoshop®本機格式。

在Aspose.Imaging for .NET v20.2中，支持TIFF格式的不同柵格數據類型，優化Tiff和Gif格式的速度或內存，添加矢量和多頁圖像的新類，修復多項格式轉換時發生的異常，接下來我們用示例演示新增的功能。

>>歡迎下載Aspose.Imaging for .NET v20.2體驗

新增與改善

key	概述	類別
IMAGINGNET-3624	支持TIFF格式的不同柵格數據類型	功能
IMAGINGNET-3588	將TIFF轉換為PNG的異常	功能
IMAGINGNET-3409	允許針對Tiff格式的速度或內存優化策略	功能
IMAGINGNET-3408	允許針對Gif格式的速度或內存優化策略	功能
IMAGINGNET-3364	統一處理多頁圖像導出	功能
IMAGINGNET-2548	介紹矢量和多頁圖像的新類	功能
IMAGINGNET-3633	將Tiff圖片轉換為PNG的異常	增強功能
IMAGINGNET-3632	將jpeg轉換為pdf的異常	增強功能
IMAGINGNET-3631	將JPG轉換為PDF時的異常	增強功能
IMAGINGNET-3623	QA 19.11 .NET 3549不透明零件	增強功能

新功能用法示例

IMAGINGNET-3624支持TIFF格式的不同柵格數據類型

示例一：根據其自身的原始數據格式加載原始數據。

// Raw data after decoding is processed to eliminate format-specific effects (prediction and invert color component values).
using (RasterImage image = (RasterImage)Image.Load("input.tif"))
{
image.LoadRawData(image.Bounds, image.RawDataSettings, new CustomRawDataLoader());
}

示例二：根據用戶指定的原始數據格式加載原始數據。

// In this case, in addition, raw data is converted from its own format to the one specified by the user.
// Note that so far not all raw data formats can be converted to other formats (since not all color converters are still implemented and registered at the ColorConverterFactory).
using (RasterImage image = (RasterImage)Image.Load("input.tif"))
{
   RawDataSettings rawDataSettings = new RawDataSettings()
          {
             PixelDataFormat = PixelDataFormat.Rgb24Bpp,
             DitheringMethod = DitheringMethods.PaletteIgnore,
          };
   rawDataSettings.LineSize =
       ((image.Width * rawDataSettings.PixelDataFormat.BitsPerPixel) + 7) / 8;

image.LoadRawData(image.Bounds, image.RawDataSettings, new CustomRawDataLoader());
}

示例三：加載未經處理的原始原始數據。

// Format-specific effects (prediction and invert color component values) may be present in this data, therefore this data cannot be used in color converters without pre-processing.
using (RasterImage image = (RasterImage)Image.Load("input.tif"))
{
image.LoadRawData(image.Bounds, null, new CustomRawDataLoader());
}

// Custom raw data loader
class CustomRawDataLoader : IPartialRawDataLoader
{
   ////// Processes the loaded data.
   //////The data rectangle.///The raw data.///The start data point. If not equal to (left,top) meaning that it is not full rectangle we have.///The end data point. If not equal to (right,bottom) meaning that it is not full rectangle we have.public void Process(Rectangle rectangle, byte[] data, Point start, Point end)
    {
       this.Process(rectangle, data, start, end, null);
    }

   ////// Processes the loaded data.
   //////The data rectangle.///The raw data.///The start data point. If not equal to (left,top) meaning that it is not full rectangle we have.///The end data point. If not equal to (right,bottom) meaning that it is not full rectangle we have.///The load options.public void Process(Rectangle rectangle, byte[] data, Point start, Point end, LoadOptions loadOptions)
    {
       // custom raw data processing
    }
}

IMAGINGNET-3623 QA 19.11 .NET 3549不透明零件

using (Image image = Image.Load("sample_car.svg"))
{
 image.Resize(image.Width * 2, image.Height * 2);
 image.Save("sample_car_resize_2_2.png", new PngOptions());
}

IMAGINGNET-3409允許對Tiff格式進行速度或內存優化的策略

// Setting a memory limit of 10 megabytes for target loaded image
using (Image image = Image.Load("Default.tiff", new LoadOptions { BufferSizeHint = 10 }))
{
   image.Save("Default_export.tiff", new TiffOptions(TiffExpectedFormat.Default));
}

using (Image image = Image.Load("TiffCcitRle.tiff", new LoadOptions { BufferSizeHint = 10 }))
{
   image.Save("TiffCcitRle_export.tiff", new TiffOptions(TiffExpectedFormat.TiffCcitRle));
}

using (Image image = Image.Load("TiffDeflateRgb.tiff", new LoadOptions { BufferSizeHint = 10 }))
{
   image.Save("TiffDeflateRgb_export.tiff", new TiffOptions(TiffExpectedFormat.TiffDeflateRgb));
}

using (Image image = Image.Load("TiffJpegYCbCr.tiff", new LoadOptions { BufferSizeHint = 10 }))
{
   image.Save("TiffJpegYCbCr_export.tiff", new TiffOptions(TiffExpectedFormat.TiffJpegYCbCr));
}

using (Image image = Image.Load("TiffLzwCmyk.tiff", new LoadOptions { BufferSizeHint = 10 }))
{
   image.Save("TiffLzwCmyk_export.tiff", new TiffOptions(TiffExpectedFormat.TiffLzwCmyk));
}

using (Image image = Image.Load("TiffNoCompressionRgb.tiff", new LoadOptions { BufferSizeHint = 10 }))
{
   image.Save("TiffNoCompressionRgb_export.tiff", new TiffOptions(TiffExpectedFormat.TiffNoCompressionRgb));
}

IMAGINGNET-3408允許Gif格式的速度或內存優化策略

// Setting a memory limit of 10 megabytes for target loaded image
using (Image image = Image.Load("flowers.gif", new LoadOptions { BufferSizeHint = 10 }))
{
   image.Save("flowers_export.gif", new GifOptions());
}

IMAGINGNET-3364統一處理多頁圖像輸出

string baseFolder = "D:\\images";
string outputFolderName = Path.Combine(baseFolder, "out");
string[] files = new[] { "MultiframePage1.dicom", "VariousObjectsMultiPage.odg" };

foreach (string inputFileName in files)
 {
   using (Image image = Image.Load(Path.Combine(baseFolder, inputFileName)))
    {
      PdfOptions imageOptions = new PdfOptions();
      imageOptions.MultiPageOptions = new MultiPageOptions(new IntRange(1, 2));                    
      if (image is VectorImage)
       {
          imageOptions.VectorRasterizationOptions = (VectorRasterizationOptions)image.GetDefaultOptions(new object[] { Color.White, image.Width, image.Height });
          imageOptions.VectorRasterizationOptions.TextRenderingHint = TextRenderingHint.SingleBitPerPixel;
          imageOptions.VectorRasterizationOptions.SmoothingMode = SmoothingMode.None;
        }

      string outFileName = Path.Combine(outputFolderName, inputFileName + ".pdf");
      image.Save(outFileName, imageOptions);
    }
 }

IMAGINGNET-2548引入矢量和多頁圖像的新類

1. 引入了抽象類VectorImage。并且庫中的所有矢量圖像都從此類繼承。位圖圖像是從RasterImage繼承的。這樣就可以唯一地分離光柵圖像和矢量圖像。

   using (Image image = Image.Load(fileName))  
   {  
    if (image is VectorImage)  
    {  
    ...  
    } 
    else 
    {  
    ...  
    }
   }

2. 引入了IMultipageImage接口，借助它可以確定圖像是否包含圖層/頁面/框架。所有多頁圖像（例如PSD，CDR，GIF等）都是該接口的后代。借助Pages屬性，您可以訪問庫中任何多頁圖像的頁面。

   using (Image image = Image.Load(fileName))  
   { 
    if (image is IMultipageImage) 
    {  
    var pages = ((IMultipageImage)image).Pages; 
    }  
   } 

3. 有了MultiPageOptions選項，導出多頁圖像變得更加容易。使用此選項，可以指定要導出為其他格式的頁面。在導出為單頁格式的情況下，將導出該范圍的第一頁；如果導出為多頁面格式，則將導出該范圍的所有頁面。
   從多頁格式導出到單頁的示例：

   int startPage = 3; 
   int countPage = 2; 
   using (Image image = Image.Load(fileName)) 
   { 
    PngOptions pngOptions = new PngOptions(); 
    pngOptions.MultiPageOptions = new MultiPageOptions(new IntRange(startPage, countPage));  
    image.Save(outFileName, pngOptions); 
   }