android - 使用 path.lineTo() 时对角线看起来比直线粗

Question

我创建了一个扩展 Shape 的类，以便为我的按钮背景绘制自定义形状(带切角的矩形)。我遇到的问题是画成对角线的线看起来比直线粗得多:

如何使边框始终保持一致的宽度？我尝试将抗锯齿设置为 true/false，但这没有任何区别

public class ShapeMaker extends Shape {
private float STROKE_WIDTH = 20.0f;

private final Paint border = new Paint();
private final Path path;


private float tl = 0; //Top Left
private float tr = 0; //Top Right
private float bl = 0; //Bottom Left
private float br = 0; //Bottom Right


public ShapeMaker(float tl, float tr, float bl, float br, int fillColor) {
    path = new Path();
    this.tl = tl;
    this.tr = tr;
    this.bl = bl;
    this.br = br;

    border.setColor(fillColor);
    border.setStyle(Paint.Style.STROKE);
    border.setStrokeWidth(STROKE_WIDTH);
    border.setAntiAlias(true);
    border.setDither(true);
    border.setStrokeJoin(Paint.Join.ROUND);
    border.setStrokeCap(Paint.Cap.ROUND);
}

@Override
protected void onResize(float width, float height) {
    super.onResize(width, height);
    path.reset();

    path.moveTo(0 + tl, 0);
    path.lineTo(width - tr, 0);
    path.lineTo(width, tr);
    path.lineTo(width, height-br);
    path.lineTo(width-br, height);
    path.lineTo(0+bl, height);
    path.lineTo(0, height-bl);
    path.lineTo(0, 0+tl);
    path.lineTo(0 + tl, 0);

    path.close();
}

@Override
public void draw(Canvas canvas, Paint paint) {
    canvas.drawPath(path, border);
}
}

用法:

Button button = findViewById(R.id.buttom);
float den = getResources().getDisplayMetrics().density;
button.setBackground(new ShapeDrawable(new ShapeMaker(den * 15, 0, 0, 0, Color.RED)));

Answer 1

简短的回答是将您的线条向内“移动”(远离 View 的边缘)，移动量等于笔划宽度的一半。

您的路径精确追踪您视野的边缘。实际绘制笔划时，它以这条路径为中心。这意味着一半的笔画在 View 的边界之外，因此被剪掉了。

但是，当您绘制路径的对角线部分时，您完全在 View 的边界内绘制，因此不会发生裁剪。这使得对角笔划看起来是其余笔划的两倍粗。

这是我编写的代码的等价物:

int inset = (int) border.getStrokeWidth() / 2;

path.reset();
path.moveTo(notch + inset, inset);
path.lineTo(width - inset, inset);
path.lineTo(width - inset, height - inset);
path.lineTo(inset, height - inset);
path.lineTo(inset, notch + inset);
path.close();