使用Canvas Android在填充的矩形内绘制文本 [英] Draw text inside a filled rectangle using Canvas Android

问题描述

如何绘制具有指定范围的填充矩形，并在要使用Canvas Android绘制的矩形文本内绘制该矩形？我尝试过

How to draw a filled rectangle with specified bounds and inside that rectangle text to be drawn using Canvas Android ?? I tried

mPaint.setColor(Color.GREEN);
canvas.drawText(mText, x, y, mPaint);
mPaint.setColor(Color.BLACK);
canvas.drawRect(x, y, x + w, y + h, mPaint);

但文本不在该矩形内。有什么伙伴可以告诉我如何在考虑文字大小的情况下在指定文字周围绘制矩形吗？

but text is not inside of that rectangle. Can any buddy tell me how to draw a rectangle surrounding specified text with consideration of text size ??

推荐答案

在这里，我对x和y值进行了硬编码。您可以更改它们

Here i have hardcoded x and y values. You can change them

        mpaint= new Paint();
        mpaint.setColor(Color.RED);
        mpaint.setStyle(Style.FILL);
        paint2= new Paint();
        paint2.setColor(Color.GREEN);
        paint2.setTextSize(50);  //set text size
        float w = paint2.measureText(s)/2;
        float textSize = paint2.getTextSize();


        @Override
        protected void onDraw(Canvas canvas) {
            paint2.setTextAlign(Paint.Align.CENTER);
            canvas.drawRect(300-w, 300 - textsize, 300 + w, 300, mpaint);
            canvas.drawText(s, 300, 300 ,paint2); //x=300,y=300    
        }

编辑：

在 onDraw 中调用 measureText 是一个好主意。您可以在 onDraw 之外进行此操作。

Its bad a idea to call measureText in onDraw. You can do that outside of onDraw.

还有一个有关性能以及为什么要避免分配的视频。在 onDraw 中。 https://www.youtube.com/watch?v=HAK5acHQ53E

There is a video on also about performance and why you should avoid allocations in onDraw. https://www.youtube.com/watch?v=HAK5acHQ53E

结果快照

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