WPF实际尺寸打印控件 [英] Real size WPF controls for printing

问题描述

我目前正在开发一个应用程序，用户可以在其中动态创建/移动画布上的TextBlocks。一旦他们将TextBlocks放置在所需的位置，就可以按下打印按钮，这将使ZPL打印机打印屏幕上当前显示的内容。

I am currently developing an application where users can create/move TextBlocks on a canvas dynamically. Once they have positioned the TextBlocks where they want them they can press a print button which will cause a ZPL printer to print what is currently displayed on screen.

ZPL命令是通过从每个TextBlock中获取以下值来构建：

The ZPL commands are built by taking the following values from each TextBlock:

• XPosition = Canvas.Left


• YPosition = Canvas.Right


• 文本=文本

但是我找不到一种获取方法打印输出类似于屏幕显示。我猜这是因为Canvas.Left和Canvas.Right的值与打印机DPI不匹配。

However I can't find a way of getting the printout to resemble the on screen display. I guess this is because the values of Canvas.Left and Canvas.Right do not match up with the printers DPI.

这是我当前正在使用的转换（因为我认为Canvas.Left = 1表示1/96英寸）（画布的左上角是0， 0）

Here is the conversion I am currently using (because I thought the Canvas.Left = 1 means 1/96th of an inch) (Top left of the canvas is 0,0)

public double GetZplXPosition(UIElement uiElement)
{
    int dpiOfPrinter = 300;
    double zplXPosition = (Canvas.GetLeft(uiElement) / 96.0) * dpiOfPrinter;
    return zplXPosition;
}

我可以在那里显示实际大小的控件。使用的纸张将始终为A5（8.3英寸x 5.8英寸）。

Is there I can display controls in "real size". The paper being used will always be A5 (8.3 in x 5.8 in).

我考虑过在画布的宽度和高度设置为830 x的情况下使用视图框580（比对A5的比率正确），但这没有帮助。

I thought about using a viewbox around a Canvas which had its width and height set to 830 x 580 (ratio correct for A5) however this didn't help.

任何建议？

谢谢

推荐答案

而不是您在做什么，而是对整个画布进行截屏并进行打印。

Instead of what you're doing, take a "screenshot" of the entire canvas and print that.

using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Imaging;

namespace ImageProcessing
{
    public class ImageProc
    {
        public RenderTargetBitmap GetImage(UIElement source)
        {
            double actualHeight = source.RenderSize.Height;
            double actualWidth = source.RenderSize.Width;

            if (actualHeight > 0 && actualWidth > 0)
            {
                RenderTargetBitmap renderTarget = new RenderTargetBitmap((int)actualWidth, (int)actualHeight, 96, 96, PixelFormats.Pbgra32);
                VisualBrush sourceBrush = new VisualBrush(source);

                DrawingVisual drawingVisual = new DrawingVisual();
                DrawingContext drawingContext = drawingVisual.RenderOpen();
                drawingContext.DrawRectangle(sourceBrush, null, new Rect(0, 0, actualWidth, actualHeight));
                drawingContext.Close();

                renderTarget.Render(drawingVisual);
                return renderTarget;
            }
            else
                return null;
        }
    }
}

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