我需要实现在画布上的圆形路径上绘制文本的弯曲文本。
使用
绘制圆形路径 canvas.drawTextOnPath(QUOTE, circle, 485, 20, tPaint);
但它不适用于不同长度的文本。
以下是我的班级在canavs上绘制圆形文字。
public class CircularTextVie extends View {
private String QUOTE = "";
private Path circle;
private Paint cPaint;
private Paint tPaint;
public CircularTextVie(Context context) {
super(context);
circle = new Path();
cPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
cPaint.setStyle(Paint.Style.STROKE);
cPaint.setColor(Color.LTGRAY);
cPaint.setStrokeWidth(3);
tPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
tPaint.setStyle(Paint.Style.FILL_AND_STROKE);
tPaint.setColor(Color.BLACK);
}
@Override
protected void onDraw(Canvas canvas) {
canvas.restore();
int xPos = (canvas.getWidth() /3);
int yPos = (int) ((canvas.getHeight() / 3) - ((tPaint.descent() + tPaint.ascent()) / 3)) ;
circle.addCircle(xPos, yPos, 150, Path.Direction.CW);
canvas.drawTextOnPath(QUOTE, circle, 485, 20, tPaint);
QUOTE="";
}
public void SetText(String text) {
this.QUOTE = text;
}
public void SetTypeFace(Typeface face) {
cPaint.setTypeface(face);
tPaint.setTypeface(face);
}
public void SetColor(int color) {
cPaint.setColor(color);
tPaint.setColor(color);
}
}
感谢。
答案 0 :(得分:2)
这可以通过根据文本宽度改变x和y位置来完成
定义变量
private Rect textBounds;
private int mTextWidth, mTextHeight,centerX,centerY;
在customview
的构造函数中添加以下内容textBounds = new Rect();
tPaint.getTextBounds(QUOTE, 0, QUOTE.length(), textBounds);
mTextWidth = Math.round(tPaint.measureText(QUOTE.toString())); // Use measureText to calculate width
mTextHeight = textBounds.height(); // Use height from getTextBounds()
然后在onDraw
canvas.drawCircle(centerX,centerY,150,mCirlcePaint);
circle.addCircle(centerX, centerY, 150, Path.Direction.CW);
// Note the 0 that's y offset. textdraw at circumference of the circle. Changing y you probably need to change the radius as well i guess.
canvas.drawTextOnPath(QUOTE, circle, (centerX)-(mTextWidth / 2f), 0, tPaint);
centerX,centerY是圆圈的中心,即canvaswidht / 2和canvasHeight / 2。我画了一个圆圈供参考
你好的结果
更大文字的结果
编辑:评论中的问题
所涉及的数学是使用文本长度计算半圆
radius = (float) ((mTextWidth) / (Math.PI))
。如果文字长度大于画布,则需要缩小文字大小或使用整圆radius = (float) ((mTextWidth) / (2*(Math.PI)))
。您可以考虑使用其他边缘情况来正确绘制文本。
公共类GraphicsView扩展了View {
private String QUOTE = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
private Path circle;
private Paint mCirlcePaint;
private Paint tPaint;
private Rect textBounds;
private int mTextWidth, mTextHeight, centerX, centerY;
private float radius;
public GraphicsView(Context context) {
super(context);
circle = new Path();
tPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
tPaint.setStyle(Paint.Style.FILL_AND_STROKE);
tPaint.setColor(Color.BLACK);
tPaint.setTextSize(100f);
textBounds = new Rect();
tPaint.getTextBounds(QUOTE, 0, QUOTE.length(), textBounds);
mTextWidth = Math.round(tPaint.measureText(QUOTE.toString())); // Use measureText to calculate width
mTextHeight = textBounds.height(); // Use height from getTextBounds()
mCirlcePaint = new Paint();
mCirlcePaint.setStyle(Paint.Style.FILL);
mCirlcePaint.setColor(Color.GREEN);
radius = (float) ((mTextWidth) / (Math.PI));
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
centerX = w / 2;
centerY = h / 2;
}
@Override
protected void onDraw(Canvas canvas) {
canvas.rotate(180, getWidth() / 2, getHeight() / 2);
canvas.drawCircle(centerX, centerY, radius, mCirlcePaint);
circle.addCircle(centerX, centerY, radius, Path.Direction.CW);
canvas.drawTextOnPath(QUOTE, circle, 0, 0, tPaint);
}
}