vb.net - VB.net 计算缩略图坐标以保存原始图像的裁剪

Question

我有一张预览图片，我可以在其中缩放和拖动图像，我需要保存预览图片框中显示的图像的相同部分，但要裁剪为真实图像（1274x2105 像素）。

应用

保存预览图片框（BtnSavePreview）时，图像正确，但不适用于原始图像 BtnSaveCrop，我使用下一个代码。

Private Sub BtnSavePreview_Click(sender As Object, e As EventArgs) Handles BtnSavePreview.Click

    Dim img As New Bitmap(PnlPan.Width - SystemInformation.VerticalScrollBarWidth, PnlPan.Height - SystemInformation.HorizontalScrollBarHeight)
    Dim gr As Graphics = Graphics.FromImage(img)
    gr.DrawImage(PicPreview.Image, New Rectangle(Point.Empty, img.Size), New Rectangle(-PnlPan.AutoScrollPosition.X, -PnlPan.AutoScrollPosition.Y, img.Width, img.Height), GraphicsUnit.Pixel)
    img.Save("C:\_workingFILES\image_preview_crop.jpg", Imaging.ImageFormat.Jpeg)

End Sub

Private Sub BtnSaveCrop_Click(sender As Object, e As EventArgs) Handles BtnSaveCrop.Click
    Dim CropRect As New Rectangle(-PnlPan.AutoScrollPosition.X, -PnlPan.AutoScrollPosition.Y, ImgZoomPan.Width, ImgZoomPan.Height)


    Dim Left As Integer = CropRect.Left * (ImgOrig.Width / ImgZoomPan.Width)
    Dim Top As Integer = CropRect.Top * (ImgOrig.Height / ImgZoomPan.Height)
    Dim Right As Integer = CropRect.Right * (ImgOrig.Width / ImgZoomPan.Width)
    Dim Bottom As Integer = CropRect.Bottom * (ImgOrig.Height / ImgZoomPan.Height)

    Dim img As New Bitmap(Right - Left, Bottom - Top)
    Dim gr As Graphics = Graphics.FromImage(img)
    gr.DrawImage(ImgOrig, New Rectangle(0, 0, Right - Left, Bottom - Top), New Rectangle(Right, Bottom, img.Width, img.Height), GraphicsUnit.Pixel)
    img.Save("C:\_workingFILES\image_crop.jpg", Imaging.ImageFormat.Jpeg)

End Sub

谢谢

Answer 1

一些修复现在有效：

Private Sub BtnSaveCrop_Click(sender As Object, e As EventArgs) Handles BtnSaveCrop.Click

    Dim CropRect As New Rectangle(-PnlPan.AutoScrollPosition.X, -PnlPan.AutoScrollPosition.Y, PnlPan.Width - SystemInformation.VerticalScrollBarWidth, PnlPan.Height - SystemInformation.HorizontalScrollBarHeight)

    Dim Left As Integer = CropRect.Left * (ImgOrig.Width / PicPreview.Width)
    Dim Top As Integer = CropRect.Top * (ImgOrig.Height / PicPreview.Height)
    Dim Right As Integer = CropRect.Right * (ImgOrig.Width / PicPreview.Width)
    Dim Bottom As Integer = CropRect.Bottom * (ImgOrig.Height / PicPreview.Height)


    Dim cropArea As New Rectangle(Left, Top, Right, Bottom)

    Dim img As New Bitmap(Right - Left, Bottom - Top)
    Dim gr As Graphics = Graphics.FromImage(img)
    gr.DrawImage(ImgOrig, New Rectangle(0, 0, cropArea.Width, cropArea.Height), cropArea, GraphicsUnit.Pixel)
    img.Save("C:\_workingFILES\image_crop.jpg", Imaging.ImageFormat.Jpeg)


End Sub

谢谢