android学习日记08--Paint画笔

时间:2023-03-09 22:03:12
android学习日记08--Paint画笔

Paint

  要绘图,首先得调整画笔,待画笔调整好之后,再将图像绘制到画布Canvas上,
这样才可以显示在手机屏幕上。Android 中的画笔是 Paint类,Paint 中包含了很多方法对其属性进行设置,

Paint方法一般可分两类,图形的绘制和文本的绘制
主要方法如下:(没有全部列出,大家可以查看官方文档http://android.toolib.net/reference/android/graphics/Paint.html )

                 canvas.drawColor(Color.GREEN);

                 Paint paint1 = new Paint();
canvas.drawCircle(40, 30, 20, paint1); //设置画笔无锯齿,默认有锯齿
paint1.setAntiAlias(true);
canvas.drawCircle(100, 30, 20, paint1); //设置画笔的透明度
canvas.drawText("无透明度", 100, 70, new Paint());
Paint paint2 = new Paint();
paint2.setAlpha(0x77);
canvas.drawText("半透明度", 20, 70, paint2); //设置绘制文本的锚点
canvas.drawText("锚点", 20, 90, new Paint());
Paint paint3 = new Paint(); //设置以文本的中心点绘制
paint3.setTextAlign(Paint.Align.CENTER);
canvas.drawText("锚点", 20, 105, paint3); //获取文本的长度
Paint paint4 = new Paint();
float len =paint4.measureText("文本宽度:");
canvas.drawText("文本长度:"+len, 20, 130, new Paint()); //设置画笔样式
canvas.drawRect(new Rect(20,140,40,160), new Paint());
Paint paint5 = new Paint(); //设置画笔不填充
paint5.setStyle(Style.STROKE);
canvas.drawRect(new Rect(60,140,80,160), paint5); //设置画笔颜色
Paint paint6 = new Paint();
paint6.setColor(Color.GRAY);
canvas.drawText("灰色", 30, 180, paint6); //设置画笔的粗细程度
canvas.drawLine(20, 200,70, 200, new Paint());
Paint paint7 = new Paint();
paint7.setStrokeWidth(7);
canvas.drawLine(20, 220,70, 220,paint7); //设置画笔绘制文本的字体粗细
Paint paint8 = new Paint();
paint8.setTextSize(20);
canvas.drawText("文字尺寸", 20, 260, paint8); //设置画笔的ARGB分量 ,a值 (透明度)
Paint paint9 = new Paint();
paint9.setARGB(0x77, 0xff, 0x00, 0x00);
canvas.drawText("红色半透明", 20, 290, paint9);

android学习日记08--Paint画笔