从picturebox C#打印高质量的Tiff文档

Question

我正在使用 WinForms。我的程序将 .Tiff 图像文档打开到一个图片框中。我遇到的问题是从图片框打印高质量的 tiff 图像。我已经多次尝试和测试过打印。当文档打印时，文字不清晰/清晰，有点模糊。我还测试了我的打印机，以检查我的打印机是否有问题。我使用 Microsoft Word 打印了一个普通的文本文档，并且打印的很清楚，所以我的代码有问题。

有人可以向我提供在我的图片框中打印高质量 .tiff 图像的代码吗？我是否需要以编程方式增加 DPI 以提高图像质量？

这是我的代码。

    private void DVPrintDocument_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
    {

        e.Graphics.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
        e.Graphics.DrawImage(pictureBox1.Image, 25, 25, 800, 1050);

    }


    private void Print_button_Click(object sender, EventArgs e)
    {
        PrintPreviewDialog.Document = PrintDocument;
        PrintPreviewDialog.ShowDialog();
    }

在进一步分析我的代码后，我想我明白了为什么我的图片变得模糊。当我打开 Tiff 文档时，我的表单中有多个 tiff 页面的后退和前进按钮。在 RefreshImage 方法中，我认为这就是我的图像变得模糊的地方。这是我的代码：

    private int intCurrPage = 0; // defining the current page (its some sort of a counter)
    bool opened = false; // if an image was opened

    //-------------------------------------Next and Back Button-------------------------------------------------

    private void btn_Back_Click(object sender, EventArgs e)
    {
        if (opened) // the button works if the file is opened. you could go with button.enabled
        {
            if (intCurrPage == 0) // it stops here if you reached the bottom, the first page of the tiff
            { intCurrPage = 0; }
            else
            {
                intCurrPage--; // if its not the first page, then go to the previous page
                RefreshImage(); // refresh the image on the selected page
            }
        }
    }

    private void btn_Next_Click(object sender, EventArgs e)
    {
        if (opened) // the button works if the file is opened. you could go with button.enabled
        {
            if (intCurrPage == Convert.ToInt32(lblNumPages.Text)) // if you have reached the last page it ends here
                                                                  // the "-1" should be there for normalizing the number of pages
            { intCurrPage = Convert.ToInt32(lblNumPages.Text); }
            else
            {
                intCurrPage++;
                RefreshImage();
            }
        }
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        var bm = new Bitmap(pictureBox1.Image);
        bm.SetResolution(600, 600);
        Image image1 = new Bitmap(bm);
        pictureBox1.Image = image1;
        pictureBox1.Refresh();
    }

    public void RefreshImage()
    {
        Image myImg; // setting the selected tiff
        Image myBmp; // a new occurance of Image for viewing

        myImg = System.Drawing.Image.FromFile(@lblFile.Text); // setting the image from a file

        int intPages = myImg.GetFrameCount(System.Drawing.Imaging.FrameDimension.Page); // getting the number of pages of this tiff
        intPages--; // the first page is 0 so we must correct the number of pages to -1
        lblNumPages.Text = Convert.ToString(intPages); // showing the number of pages
        lblCurrPage.Text = Convert.ToString(intCurrPage); // showing the number of page on which we're on

        myImg.SelectActiveFrame(System.Drawing.Imaging.FrameDimension.Page, intCurrPage); // going to the selected page

        myBmp = new Bitmap(myImg, pictureBox1.Width, pictureBox1.Height); // setting the new page as an image
        // Description on Bitmap(SOURCE, X,Y)

        pictureBox1.Image = myBmp; // showing the page in the pictureBox1

    }

Answer 1

    myBmp = new Bitmap(myImg, pictureBox1.Width, pictureBox1.Height); 
    pictureBox1.Image = myBmp;

别再犹豫了，您正在重新缩放图像以适合图片框。这会丢弃源图像中的大量像素，图片框比图像小很多。顺便说一句，长宽比只是偶然正确的。

最简单的方法是不自己重新调整大小，而将其留给 PictureBox 控件来完成。尽管这会使绘画速度变慢。另一种方法是简单地保留对原始图像的引用。只需使用变量而不是 PictureBox.Image 属性。