放大使用canvas.scale功能的印刷品吗？ [英] Zoom in a canvas using canvas.scale function?

问题描述

我已经实现了它绘制一组矩形长的OnDraw方法。矩形太小，我希望他们能够出现较大。但遗憾的是我不能改变的矩形坐标becoz它们存储在数据库中。那么，有什么办法可以在画布上用canvas.scale（缩小）？

I have implemented a long Ondraw method which draws a set of rectangles. the rectangles are too small and i want them to appear bigger. But unfortunately i cant change the rectangle coordinates becoz they are stored in a database. So is there any way i can Zoom in the canvas using the canvas.scale() ?

推荐答案

我说，你将需要绘制的一切，在0,0，然后扩展它，最后它翻译成去preface这个答案表现正常。

I'm going to preface this answer by saying you will need to draw everything at 0,0 and then scale it, and finally translate it to behave properly.

根本就在你的OnDraw方法如下：

Simply do the following in your onDraw method:

canvas.save();
    canvas.translate(xValue, yValue);
    canvas.scale(xScale, yScale)
    /* draw whatever you want scaled at 0,0*/
canvas.restore();

xScale等收缩或伸展在X方向， yScale收缩或伸展在Y方向。

xScale shrinks or stretches in the X direction, yScale shrinks or stretches in the Y direction.

1.0是默认了这些，所以2.0可以拓展它采用双和0.5将减半缩水了。

1.0 is the default for these, so 2.0 would stretch it by double and 0.5 would shrink it by half.

例如：

canvas.save();
    canvas.translate(50, 50);
    canvas.scale(0.5f, 0.5f);
    canvas.drawRect(0.0, 0.0, 5.0, 5.0, paint);
canvas.restore();

这将吸引长度5.0一个矩形，宽5.0，比例缩小到2.5的长度和宽度，然后将其移动到（50，50）。

This will draw a rectangle with length 5.0, and width 5.0, scale it down to 2.5 for length and width, and then move it to (50, 50).

结果将是，如果你这样做矩形得出：

The result will be a rectangle drawn as if you did this:

canvas.drawRect(50.0, 50.0, 52.5, 52.5, paint);

我希望这有助于！

I hope this helps!

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