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我需要处理大型单色图像。我基本上需要将横幅（框架和格式化文本）添加到高分辨率（如 30000x20000px）单色图像（400dpi 的 A2+ 绘图）。

默认PixelFormat为Format1bppIndexed，这使得即使是那些大图片的尺寸也相对较小。但是，使用 .NET GDI+Graphics对象需要未索引的位图。

将图像转换为最低可用 unindexed 时PixelFormat.Format16bppGrayscale：

bmpResized = ImgResized.Clone(New System.Drawing.Rectangle(0, 0, ImgResized.Width, ImgResized.Height),
             System.Drawing.Imaging.PixelFormat.Format16bppGrayScale)

...它变得很大，可以由Image和处理Bitmap（OutOfMemoryExeption: Not enough memory- 在 32GB 机器上）。我尝试单独创建横幅并以像素方式加入图片，但是我遇到了同样的限制 -SetPixel需要未索引的位图。

有没有办法克服这些问题？

编辑：一个可能的解决方案是创建一个字节数组并根据 [https://social.msdn.microsoft.com/Forums/vstudio/en-US/54a096ff-46f3-45ce-8560-bf5a0618ef75/how 编辑字节-to-set-pixel-into-bitmap-with-pixel-format-of-format8bppindexed-?forum=csharpgeneral][1]。但是我不确定我如何能按字节“移动”第二张图像。
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1 回答 1

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最后我不得不使用按位操作来完成它。结果很完美，甚至表现也非常好。

' Create byte array for the main ploted TIF image
Dim bmp As New Drawing.Bitmap(Img.Width, Img.Height, Drawing.Imaging.PixelFormat.Format1bppIndexed)
bmp = Img   ' getting bitmap from the default image
Dim data As System.Drawing.Imaging.BitmapData = bmp.LockBits(New Drawing.Rectangle(0, 0, bmp.Width, bmp.Height), Drawing.Imaging.ImageLockMode.[WriteOnly], Drawing.Imaging.PixelFormat.Format1bppIndexed)
Dim bytes As Byte() = New Byte(data.Height * data.Stride - 1) {}
System.Runtime.InteropServices.Marshal.Copy(data.Scan0, bytes, 0, bytes.Length)


' Create byte array for the banner
Dim bmpB As New Drawing.Bitmap(Img.Width, Img.Height, Drawing.Imaging.PixelFormat.Format1bppIndexed)
bmpB = Img.Clone()   ' banner had to be generated in 16bppp unindexed gray scale image to be able to use graphics
Dim dataB As System.Drawing.Imaging.BitmapData = bmpB.LockBits(New Drawing.Rectangle(0, 0, BmpB.Width, BmpB.Height), Drawing.Imaging.ImageLockMode.[WriteOnly], Drawing.Imaging.PixelFormat.Format1bppIndexed)
Dim bytesB As Byte() = New Byte(dataB.Height * dataB.Stride - 1) {}
System.Runtime.InteropServices.Marshal.Copy(dataB.Scan0, bytesB, 0, bytesB.Length)


' Join byte arrays:  Resulting bitmap = plotted TIF + banner
Dim bytesResult((bytes.Length + bytesB.Length) - 1) As Byte
bytesB.CopyTo(bytesResult, 0)
bytes.CopyTo(bytesResult, bytesB.Length)


' Revert resulting byte array back to bitmap and save resulting TIF image
BmpResized = New Bitmap(Img.Width, Img.Height * 2, Drawing.Imaging.PixelFormat.Format1bppIndexed)
Dim dataResult As System.Drawing.Imaging.BitmapData = BmpResized.LockBits(New Drawing.Rectangle(0, 0, BmpResized.Width, BmpResized.Height), Drawing.Imaging.ImageLockMode.[WriteOnly], Drawing.Imaging.PixelFormat.Format1bppIndexed)
System.Runtime.InteropServices.Marshal.Copy(bytesResult, 0, dataResult.Scan0, bytes.Length + bytesB.Length - 0)
Dim exportFileName As String = filenames1(0).Replace(".tif", "_mod.tif")
exportFileName = exportFileName.Replace(".png", "_mod.tif")
BmpResized.Save(exportFileName, Drawing.Imaging.ImageFormat.Tiff)

' Unlock locked bitmaps
bmp.UnlockBits(dataResult)
BmpResized.UnlockBits(dataResult)

' dispose anything not used later...
于 2021-06-30T18:32:28.797 回答