在 VB.Net 中从头开始创建位图图像时，质量很差？

Question

Vb.Net 应用程序从头开始创建位图并将其转换为 tiff 或将其发送到打印机。在这两种情况下，图像的质量（在这种情况下是字体）都不好。下面列出的示例代码创建了我用来写入图像的图形对象。

Dim gr2 As Graphics = Graphics.FromImage(New Bitmap(800, 1000), Imaging.PixelFormat.Format32bppPArgb))

Answer 1

除了@durilai 所说的，如果您要打印，您可能希望提高分辨率。 .Net 使用的系统分辨率通常为 96 DPI，但打印机可以处理 300 DPI 或更高的文件。

    'Create a new bitmap
    Using Bmp As New Bitmap(800, 1000, Imaging.PixelFormat.Format32bppPArgb)
        'Set the resolution to 300 DPI
        Bmp.SetResolution(300, 300)
        'Create a graphics object from the bitmap
        Using G = Graphics.FromImage(Bmp)
            'Paint the canvas white
            G.Clear(Color.White)
            'Set various modes to higher quality
            G.InterpolationMode = Drawing2D.InterpolationMode.HighQualityBicubic
            G.SmoothingMode = Drawing2D.SmoothingMode.AntiAlias
            G.TextRenderingHint = Drawing.Text.TextRenderingHint.AntiAlias

            'Create a font
            Using F As New Font("Arial", 12)
                'Create a brush
                Using B As New SolidBrush(Color.Black)
                    'Draw some text
                    G.DrawString("Hello world", F, B, 20, 20)
                End Using
            End Using
        End Using

        'Save the file as a TIFF
        Bmp.Save("c:\test.tiff", Imaging.ImageFormat.Tiff)
    End Using

Answer 2

我使用了这些方法，尝试使用它们会产生巨大的影响。这些是 C#，但您可以看到需要什么。对不起。

  Bitmap bm = new Bitmap(iWidth, iHeight);
  using (Graphics graphics = Graphics.FromImage(bm))
  {
    graphics.CompositingMode = System.Drawing.Drawing2D.CompositingMode.SourceCopy;
    graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
    graphics.DrawImage(bmOriginal, 0, 0, iWidth, iHeight);
  }

我对字体使用了这些方法：

  graphics.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighSpeed;
  graphics.TextRenderingHint = TextRenderingHint.AntiAlias;