Question

我已经创建了一个简单的测试来显示这个问题，这是使用C＃winform的演示代码：

private void Form1_Paint(object sender, PaintEventArgs e)
    {
        e.Graphics.Clear(Color.FromArgb(255, 41, 41, 41));

        float distance = 20;

        for (int i = 1; i < 25; ++i)
        {
            if (i <= 10)
            {
                using (Pen p = new Pen(Color.White, ((float)i) / 10))
                {
                    e.Graphics.DrawLine(p, new PointF(0, i * distance + 10), new PointF(this.Width, i * distance + 10));
                }

            }
            else if (i == 11)
            {
                using (Pen p = new Pen(Color.Red, 1.0f))
                {
                    e.Graphics.DrawLine(p, new PointF(0, i * distance + 10), new PointF(this.Width, i * distance + 10));
                }
            }
            else
            {
                using (Pen p = new Pen(Color.White, i-11))
                {
                    e.Graphics.DrawLine(p, new PointF(0, i * distance + 10), new PointF(this.Width, i * distance + 10));
                }
            }
        }
    }

这是代码使用sharpdx做同样的事情：

 private void renderControl_Paint(object sender, PaintEventArgs e)
    {
        try
        {
            RenderTarget2D.BeginDraw();

            RenderTarget2D.Clear(new Color(41, 41, 41, 255));

            float distance = 20;

            for(int i=1; i<25; ++i)
            {
                if(i<=10)
                {
                    RenderTarget2D.DrawLine(new RawVector2(0, i * distance + 10), new RawVector2(renderControl.Width, i * distance + 10),
                        SceneColorBrush,
                        ((float)i) / 10.0f
                        );
                }
                else if (i == 11)
                {
                    RenderTarget2D.DrawLine(new RawVector2(0, i * distance + 10), new RawVector2(renderControl.Width, i * distance + 10),
                    FlagSceneColorBrush,
                    i - 10
                    );
                }
                else
                {
                    RenderTarget2D.DrawLine(new RawVector2(0, i * distance + 10), new RawVector2(renderControl.Width, i * distance + 10),
                        SceneColorBrush,
                        i - 11
                        );
                }
            }

            RenderTarget2D.EndDraw();
        }
        catch (Exception ex)
        {
            LogException(ex);
        }
    }

wpf测试代码：

protected override void OnRender(DrawingContext drawingContext)
    {
        base.OnRender(drawingContext);

        drawingContext.DrawRectangle(BackgroundBrush, BackgroundPen, new Rect(0, 0, Width, Height));

        float distance = 20;

        for (int i = 1; i < 25; ++i)
        {
            if (i <= 10)
            {
                Pen p = new Pen( myLineBrush, ((float)i) / 10 );
                drawingContext.DrawLine(p, new Point(0, i * distance + 10), new Point(this.Width, i * distance + 10));                    
            }
            else if (i == 11)
            {                    
                Pen p = new Pen(myFlagLineBrush, 1.0f);
                drawingContext.DrawLine(p, new Point(0, i * distance + 10), new Point(this.Width, i * distance + 10));
            }
            else
            {
                myLineBrush.Color = Color.FromArgb(255, 255, 255, 255);

                Pen p = new Pen(myLineBrush, i - 11);
                drawingContext.DrawLine(p, new Point(0, i * distance + 10), new Point(this.Width, i * distance + 10));
            }
        }

    }

请查看此图片我已按比例缩放：

你可以看到，direct2d绘制所有的线都使用两个像素，而gdi +使用一个像素。因此它使得direct2d绘制的线看起来比gid +线更粗。我已经在wpf中测试了这段代码并使用DrawingContext绘制了线条，它与direct2d具有相同的结果。我发现direct2d drawline函数中有一个参数。

virtual void DrawLine(
             D2D1_POINT_2F    point0,
             D2D1_POINT_2F    point1,
             ID2D1Brush       *brush,
             FLOAT            strokeWidth = 1.0f,
             ID2D1StrokeStyle *strokeStyle = NULL ) = 0;

当我将行程改为小于1.0时，它只会使线条变暗，而不会使线条变得更薄。所以我想知道，如何更改direct2d / wpf行的默认像素宽度？让它只在屏幕上像GDI +一样，谢谢。

为什么direct2d行和wpf行总是在屏幕上占用两个像素？

0 个答案: