游戏开发基础part3--Paint 画笔
Paint画笔是绘图的辅助类，一般它是作为画布的参数来实现相应的效果，Paint类中包含文字与位图的样式、颜色等属性信息。Paint的常用方法如下：
1.setAntiAlias(boolean aa)
作用：设置画笔是否无锯齿
参数：true表示无锯齿，false表示有锯齿，默认为flase。
2.setAlpha(int a)
作用：设置画笔透明度
参数：透明度
3.setTextAlign(Paint.Align align)
作用：设置绘制文本的锚点
参数：Paint.Align类中的常量
4.measureText(String text)
作用：获取文本内容的宽度
参数：文本内容
5.setStyle(Style style)
作用：设置画笔样式
参数：样式实例
6.setColor(int color)
作用：设置画笔颜色
参数：色值
7.setStrokeWidth(float width)
作用：设置画笔的粗细程度
参数；画笔粗细值
8.setTextSize(float textSize)
作用：设置画笔在绘制文本时，文本字体的尺寸
参数：尺寸值
9.setARGB(int a, int r ,int g, int b)
作用：设置画笔的ARGB分量
第一个参数：画笔透明度分量
第二个参数：画笔红色分量
第三个参数：画笔绿色分量
第四个参数：画笔蓝色分量
创建项目实例：PaintProject
项目运行效果：
项目源代码：
==>MySurfaceView.java
package com.paint;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.Rect;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;
public class MySurfaceView extends SurfaceView implements Callback {
//用于控制SurfaceView
private SurfaceHolder sfh;
private Paint paint;
private Canvas canvas;
public MySurfaceView(Context context) {
super(context);
//实例SurfaceHolder
sfh = this.getHolder();
//为SurfaceView添加状态监听
sfh.addCallback(this);
//实例一个画笔
paint = new Paint();
//设置画笔颜色为白色
paint.setColor(Color.WHITE);
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
// TODO Auto-generated method stub
myDraw();
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
// TODO Auto-generated method stub
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
// TODO Auto-generated method stub
}
/**
* 自定义绘图函数
*/
public void myDraw(){
try{
canvas = sfh.lockCanvas();
if (canvas != null){
canvas.drawColor(Color.WHITE);
//----设置画笔无锯齿
Paint paint1 = new Paint();
canvas.drawCircle(40, 30, 20, paint1);
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(60,140,40,160), 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ARGB分量
Paint paint9 = new Paint();
paint9.setARGB(0x77, 0xff, 0x00, 0x00);
canvas.drawText("红色半透明", 20, 290, paint9);
}
} catch(Exception e){
}finally{
if(canvas != null)
sfh.unlockCanvasAndPost(canvas);
}
}
}