如何在GDI+中移动缩放线

本文关键字：移动 缩放 GDI+ | 更新日期: 2023-09-27 18:17:54

我有一个图片框。在图片框中，我使用:

gfx.DrawLine(nPen, line.xBegin, line.yBegin, line.xEnd, line.yEnd);

line是包含行起始值和行结束值的对象。

我在那个图片框上画了10条线。我的mouse_Wheel监听器包含以下代码:

gfx.TranslateTransform((panelpreview.Width) / 2, (panelpreview.Height) / 2);
gfx.ScaleTransform(imageScale, imageScale);
gfx.TranslateTransform(-(panelpreview.Width) / 2, -(panelpreview.Height) / 2);

当前我正在尝试移动行:

    private void panelPreview_MouseDown(object sender, MouseEventArgs e)
    {
        if (e.Button == System.Windows.Forms.MouseButtons.Left)
        {
            checkLinesIntersection(e.Location); //checks if e.Location intersects with the line
            panelPreview.MouseUp += new MouseEventHandler(panelPreview_MouseUpLine);
            panelPreview.MouseMove += new MouseEventHandler(panelPreview_MouseMoveLine);
        }
    }
    void panelPreview_MouseMoveLine(object sender, MouseEventArgs e)
    {
        if (_Leading.movable)
            newFont.Leading = e.Y - (_base.yBegin + newFont._descenderHeight);
        if (_xHeight.movable)
            if (_base.yBegin - e.Y >= 0)
                newFont.xHeight = _base.yBegin - e.Y;
        if (_capHeight.movable)
            if (_base.yBegin - e.Y >= 0)
                newFont.capHeight = _base.yBegin - e.Y;
        if (_ascenderHeight.movable)
            if (_base.yBegin - e.Y >= 0)
                newFont.ascenderHeight = _base.yBegin - e.Y;
        if (_descenderHeight.movable)
            if (e.Y - _base.yBegin >= 0)
                newFont.descenderHeight = e.Y - _base.yBegin;
        UpdatePreviewWindow();
    }
    void panelPreview_MouseUpLine(object sender, MouseEventArgs e)
    {
        panelPreview.MouseMove -= new MouseEventHandler(panelPreview_MouseMoveLine);
        panelPreview.MouseUp -= new MouseEventHandler(panelPreview_MouseUpLine);
    }

问题是，在放大后，即使我在视觉上按了行，它的反应方式不应该。

    public void checkLinesIntersection(Point mouseLocation)
    {
        lineIntersects(_Leading, mouseLocation);
        lineIntersects(_xHeight, mouseLocation);
    }
    private void lineIntersects(nLine line, Point mouseLocation)
    {
        if (mouseLocation.X >= line.xBegin && mouseLocation.X <= line.xEnd)
            if (mouseLocation.Y >= line.yBegin || mouseLocation.Y + 2 >= line.yBegin)
                if (mouseLocation.Y <= line.yEnd || mouseLocation.Y - 2 <= line.yEnd)
                    switch (line.sName)
                    {
                        case "xHeight":
                            newFont.selectedLine = nFont.Lines._xHeight;
                            break;
                        default:
                            break;
                    }
    }

如何在GDI+中移动缩放线

所以!在这个工具上工作了一段时间后，我改变了方法并使用XNA来处理图形(绘图，缩放，移动绘制对象)。对我帮助很大的是在XNA中使用Camera和Matrix进行变换。无论如何!我不打算用XNA来解决这个问题，但是通过使用XNA，我找到了在WinForms中处理它的方法。

float Zoom = 1f;
Microsoft.Xna.Framework.Rectangle mouseRect;
Matrix inverse;
void TAB_PICTURE_BOX_MouseWheel(object sender, MouseEventArgs e)
    {
        try
        {
            if (e.Delta > 0)
            {
                Zoom+= .1f;
            }
            if (e.Delta < 0)
            {
                Zoom -= .1f;
            }
            gfx.ResetTransform();
            gfx.TranslateTransform((Width + img.Width) / 2, (Height - img.Height) / 2);
            gfx.ScaleTransform(Zoom, Zoom);
            gfx.TranslateTransform(-(Width + img.Width) / 2, -(Height - img.Height) / 2);      
                getInversePosition(e);
        }
        catch (Exception ex)
        {
            Console.WriteLine(ex.Message);
        }
    }

和最后的触摸getInversePosition(e);方法:

 private void getInversePosition(MouseEventArgs e)
    {
        Matrix matrix = Matrix.CreateTranslation(new Vector3(-(Width + img.Width) / 2, -(Height - img.Height) / 2, 0)) *
                  Matrix.CreateScale(new Vector3(Zoom, Zoom, 1)) *
                  Matrix.CreateTranslation(new Vector3((Width + img.Width) / 2, (Height - img.Height) / 2, 0));
        inverse = Matrix.Invert(matrix);
        Vector2 mousePosition = Vector2.Transform(new Vector2(e.X, e.Y), inverse);
        mouseRect = new Microsoft.Xna.Framework.Rectangle((int)mousePosition.X, (int)mousePosition.Y, 1, 1);
    }

我确信有一种方法可以在没有XNA参与的情况下处理它，但在我的场景中，XNA使工作。

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