线帽
Paint.setStrokeCap(Paint.Cap.BUTT); 无线帽
Paint.setStrokeCap(Paint.Cap.ROUND); 圆形线帽
Paint.setStrokeCap(Paint.Cap.SQUARE);方形线帽
f18e0eb1379575428eefcd82d1216005.png
拐角风格
Paint.setStrokeJoin(Paint.Join.MITER); 默认
Paint.setStrokeJoin(Paint.Join.ROUND); 圆角
Paint.setStrokeJoin(Paint.Join.BEVEL); 斜角
ac20ae1c998fdb48a887833251739183.png
渲染器
线性渲染
/**
* 1.线性渲染,LinearGradient(float x0, float y0, float x1, float y1, @NonNull @ColorInt int colors[], @Nullable float positions[], @NonNull TileMode tile)
* (x0,y0)：渐变起始点坐标
* (x1,y1):渐变结束点坐标
* color0:渐变开始点颜色,16进制的颜色表示，必须要带有透明度
* color1:渐变结束颜色
* colors:渐变数组
* positions:位置数组，position的取值范围[0,1],作用是指定某个位置的颜色值，如果传null，渐变就线性变化。
* tile:用于指定控件区域大于指定的渐变区域时，空白区域的颜色填充方法
*/
mShader = new LinearGradient(0, 0, 200, 200, new int[]{Color.RED, Color.BLUE, Color.GREEN}, new float[]{0.f,0.7f,1}, Shader.TileMode.REPEAT);
mPaint.setShader(mShader);
canvas.drawRect(0,100,400,450, mPaint);
环形渲染
/**
* 环形渲染，RadialGradient(float centerX, float centerY, float radius, @ColorInt int colors[], @Nullable float stops[], TileMode tileMode)
* centerX ,centerY：shader的中心坐标，开始渐变的坐标
* radius:渐变的半径
* centerColor,edgeColor:中心点渐变颜色，边界的渐变颜色
* colors:渐变颜色数组
* stoops:渐变位置数组，类似扫描渐变的positions数组，取值[0,1],中心点为0，半径到达位置为1.0f
* tileMode:shader未覆盖以外的填充模式。
*/
mShader = new RadialGradient(650, 250, 150, new int[]{Color.GREEN, Color.YELLOW, Color.RED}, null, Shader.TileMode.CLAMP);
mPaint.setShader(mShader);
canvas.drawCircle(650, 250, 150, mPaint);
扫描渲染
/**
* 扫描渲染，SweepGradient(float cx, float cy, @ColorInt int color0,int color1)
* cx,cy 渐变中心坐标
* color0,color1：渐变开始结束颜色
* colors，positions：类似LinearGradient,用于多颜色渐变,positions为null时，根据颜色线性渐变
*/
mShader = new SweepGradient(1050, 250, Color.RED, Color.GREEN);
mPaint.setShader(mShader);
canvas.drawCircle(1050, 250, 150, mPaint);
位图渲染
/**
* 位图渲染，BitmapShader(@NonNull Bitmap bitmap, @NonNull TileMode tileX, @NonNull TileMode tileY)
* Bitmap:构造shader使用的bitmap
* tileX：X轴方向的TileMode
* tileY:Y轴方向的TileMode
REPEAT, 绘制区域超过渲染区域的部分，重复排版
CLAMP， 绘制区域超过渲染区域的部分，会以最后一个像素拉伸排版
MIRROR, 绘制区域超过渲染区域的部分，镜像翻转排版
*/
mShader = new BitmapShader(mBitmap, Shader.TileMode.REPEAT, Shader.TileMode.MIRROR);
mPaint.setShader(mShader);
canvas.drawRect(0,600,300, 800, mPaint);
组合渲染
/**
* 组合渲染，
* ComposeShader(@NonNull Shader shaderA, @NonNull Shader shaderB, Xfermode mode)
* ComposeShader(@NonNull Shader shaderA, @NonNull Shader shaderB, PorterDuff.Mode mode)
* shaderA,shaderB:要混合的两种shader
* Xfermode mode： 组合两种shader颜色的模式
* PorterDuff.Mode mode: 组合两种shader颜色的模式
*/
BitmapShader bitmapShader = new BitmapShader(mBitmap, Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);
LinearGradient linearGradient = new LinearGradient(400, 600, 900, 1100, new int[]{Color.RED, Color.GREEN, Color.BLUE}, null, Shader.TileMode.CLAMP);
mShader = new ComposeShader(bitmapShader, linearGradient, PorterDuff.Mode.MULTIPLY);
mPaint.setShader(mShader);
canvas.drawCircle(650, 850, 250, mPaint);
3911af3a313cbb49949fd720a935cae8.png
图层混合模式
// draw the border
paint.setStyle(Paint.Style.STROKE);
paint.setShader(null);
canvas.drawRect(x - 0.5f, y - 0.5f, x + W + 0.5f, y + H + 0.5f, paint);
// draw the checker-board pattern
paint.setStyle(Paint.Style.FILL);
paint.setShader(mBG);
canvas.drawRect(x, y, x + W, y + H, paint);
// 使用离屏绘制
int sc = canvas.saveLayer(x, y, x + W, y + H, null);
canvas.translate(x, y);
canvas.drawBitmap(makeDst(2 * W / 3, 2 * H / 3), 0, 0, paint);
paint.setXfermode(Xfermode.sModes[i]);
canvas.drawBitmap(makeSrc(2 * W / 3, 2 * H / 3), W / 3, H / 3, paint);
paint.setXfermode(null);
canvas.restoreToCount(sc);
//其中Sa全称为Source alpha表示源图的Alpha通道；Sc全称为Source color表示源图的颜色；Da全称为Destination alpha表示目标图的Alpha通道；Dc全称为Destination color表示目标图的颜色，[...,..]前半部分计算的是结果图像的Alpha通道值，“,”后半部分计算的是结果图像的颜色值。
//效果作用于src源图像区域
public static final PorterDuffXfermode[] sModes = {
//所绘制不会提交到画布上
new PorterDuffXfermode(PorterDuff.Mode.CLEAR),
//显示上层绘制的图像
new PorterDuffXfermode(PorterDuff.Mode.SRC),
//显示下层绘制图像
new PorterDuffXfermode(PorterDuff.Mode.DST),
//正常绘制显示，上下层绘制叠盖
new PorterDuffXfermode(PorterDuff.Mode.SRC_OVER),
//上下层都显示，下层居上显示
new PorterDuffXfermode(PorterDuff.Mode.DST_OVER),
//取两层绘制交集，显示上层
new PorterDuffXfermode(PorterDuff.Mode.SRC_IN),
//取两层绘制交集，显示下层
new PorterDuffXfermode(PorterDuff.Mode.DST_IN),
//取上层绘制非交集部分，交集部分变成透明
new PorterDuffXfermode(PorterDuff.Mode.SRC_OUT),
//取下层绘制非交集部分，交集部分变成透明
new PorterDuffXfermode(PorterDuff.Mode.DST_OUT),
//取上层交集部分与下层非交集部分
new PorterDuffXfermode(PorterDuff.Mode.SRC_ATOP),
//取下层交集部分与上层非交集部分
new PorterDuffXfermode(PorterDuff.Mode.DST_ATOP),
//去除两图层交集部分
new PorterDuffXfermode(PorterDuff.Mode.XOR),
//取两图层全部区域，交集部分颜色加深
new PorterDuffXfermode(PorterDuff.Mode.DARKEN),
//取两图层全部区域，交集部分颜色点亮
new PorterDuffXfermode(PorterDuff.Mode.LIGHTEN),
//取两图层交集部分，颜色叠加
new PorterDuffXfermode(PorterDuff.Mode.MULTIPLY),
//取两图层全部区域，交集部分滤色
new PorterDuffXfermode(PorterDuff.Mode.SCREEN),
//取两图层全部区域，交集部分饱和度相加
new PorterDuffXfermode(PorterDuff.Mode.ADD),
//取两图层全部区域，交集部分叠加
new PorterDuffXfermode(PorterDuff.Mode.OVERLAY)
};
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颜色过滤器
LightingColorFilter
/**
* R' = R * mul.R / 0xff + add.R
* G' = G * mul.G / 0xff + add.G
* B' = B * mul.B / 0xff + add.B
*/
int sc;
//原始图片效果
sc = canvas.saveLayer(0, 0, W, H, null);
canvas.drawText("原始图片", 100,50,labelP);
LightingColorFilter lighting1 = new LightingColorFilter(0xffffff,0x000000);
mPaint.setColorFilter(lighting1);
canvas.drawBitmap(mBitmap, 0,100, mPaint);
canvas.restoreToCount(sc);
//蓝色去除掉
sc = canvas.saveLayer(W, 0, W*2, H, null);
canvas.translate(W, 0);
canvas.drawText("蓝色去除掉", 100,50,labelP);
LightingColorFilter lighting2 = new LightingColorFilter(0xffff00,0x000000);
mPaint.setColorFilter(lighting2);
canvas.drawBitmap(mBitmap, 0,100, mPaint);
canvas.restoreToCount(sc);
//绿色更亮
sc = canvas.saveLayer(W*2, 0, W*3, H, null);
canvas.translate(W*2, 0);
canvas.drawText("绿色更亮", 100,50,labelP);
LightingColorFilter lighting3 = new LightingColorFilter(0xffffff,0x003000);
mPaint.setColorFilter(lighting3);
canvas.drawBitmap(mBitmap, 0,100, mPaint);
canvas.restoreToCount(sc);
ba117e660fc9f943910e5a96d22341aa.png
PorterDuffColorFilter
//图层混合红色
sc = canvas.saveLayer(0, H, W, H*2, null);
canvas.translate(0, H);
canvas.drawText("图层混合红色", 100,50,labelP);
PorterDuffColorFilter porterDuffColorFilter1 = new PorterDuffColorFilter(Color.RED, PorterDuff.Mode.DARKEN);
mPaint.setColorFilter(porterDuffColorFilter1);
canvas.drawBitmap(mBitmap, 0, 100, mPaint);
canvas.restoreToCount(sc);
//图层混合黄色
sc = canvas.saveLayer(W, H, W*2, H*2, null);
canvas.translate(W, H);
canvas.drawText("图层混合黄色", 100,50,labelP);
PorterDuffColorFilter porterDuffColorFilter2 = new PorterDuffColorFilter(Color.YELLOW, PorterDuff.Mode.DARKEN);
mPaint.setColorFilter(porterDuffColorFilter2);
canvas.drawBitmap(mBitmap, 0, 100, mPaint);
canvas.restoreToCount(sc);
//图层混合红色
sc = canvas.saveLayer(W*2, H, W*3, H*2, null);
canvas.translate(W*2, H);
canvas.drawText("图层混合紫色", 100,50,labelP);
PorterDuffColorFilter porterDuffColorFilter3 = new PorterDuffColorFilter(Color.MAGENTA, PorterDuff.Mode.DARKEN);
mPaint.setColorFilter(porterDuffColorFilter3);
canvas.drawBitmap(mBitmap, 0, 100, mPaint);
canvas.restoreToCount(sc);
54ad2658514f0140941d7176284c7801.png
ColorMatrixColorFilter
float[] colorMatrix = {
2,0,0,0,0, //red
0,1,0,0,0, //green
0,0,1,0,0, //blue
0,0,0,1,0 //alpha
};
sc = canvas.saveLayer(0, H*2, W, H*3, null);
canvas.translate(0, H*2);
canvas.drawText("颜色亮度调节-绿色", 100,50,labelP);
ColorMatrix cm1 = new ColorMatrix();
// //颜色亮度调节-绿色
cm1.setScale(1,2,1,1);
ColorMatrixColorFilter colorMatrixColorFilter1 = new ColorMatrixColorFilter(cm1);
mPaint.setColorFilter(colorMatrixColorFilter1);
canvas.drawBitmap(mBitmap, 0, 100, mPaint);
canvas.restoreToCount(sc);
sc = canvas.saveLayer(W, H*2, W*2, H*3, null);
canvas.translate(W, H*2);
canvas.drawText("饱和度调节", 100,50,labelP);
ColorMatrix cm2 = new ColorMatrix();
// //饱和度调节0-无色彩， 1- 默认效果， >1饱和度加强
cm2.setSaturation(2);
ColorMatrixColorFilter colorMatrixColorFilter2 = new ColorMatrixColorFilter(cm2);
mPaint.setColorFilter(colorMatrixColorFilter2);
canvas.drawBitmap(mBitmap, 0, 100, mPaint);
canvas.restoreToCount(sc);
sc = canvas.saveLayer(W*2, H*2, W*3, H*3, null);
canvas.translate(W*2, H*2);
canvas.drawText("色调调节", 100,50,labelP);
ColorMatrix cm3 = new ColorMatrix();
//色调调节-红色45度
cm3.setRotate(0, 45);
ColorMatrixColorFilter colorMatrixColorFilter3 = new ColorMatrixColorFilter(cm3);
mPaint.setColorFilter(colorMatrixColorFilter3);
canvas.drawBitmap(mBitmap, 0, 100, mPaint);
canvas.restoreToCount(sc);
19bb619b815f494e90acffd13312478a.png
遮罩滤镜
int W = 700;
int H = 150;
int sc;
sc = canvas.saveLayer(0, 0, W, H, null);
canvas.translate(0, 0);
canvas.drawText("内外模糊", 100,50,labelP);
mPaint.setMaskFilter(new BlurMaskFilter(10, BlurMaskFilter.Blur.NORMAL));//设置画笔遮罩滤镜 ,传入度数和样式
canvas.drawLine(100,100,W-100,100,mPaint);
canvas.restoreToCount(sc);
sc = canvas.saveLayer(0, H, W, H*2, null);
canvas.translate(0, H);
canvas.drawText("外模糊内填充", 100,50,labelP);
mPaint.setMaskFilter(new BlurMaskFilter(10, BlurMaskFilter.Blur.SOLID));//设置画笔遮罩滤镜 ,传入度数和样式
canvas.drawLine(100,100,W-100,100,mPaint);
canvas.restoreToCount(sc);
sc = canvas.saveLayer(0, H*2, W, H*3, null);
canvas.translate(0, H*2);
canvas.drawText("外模糊", 100,50,labelP);
mPaint.setMaskFilter(new BlurMaskFilter(10, BlurMaskFilter.Blur.OUTER));//设置画笔遮罩滤镜 ,传入度数和样式
canvas.drawLine(100,100,W-100,100,mPaint);
canvas.restoreToCount(sc);
sc = canvas.saveLayer(0, H*3, W, H*4, null);
canvas.translate(0, H*3);
canvas.drawText("内模糊", 100,50,labelP);
mPaint.setMaskFilter(new BlurMaskFilter(10, BlurMaskFilter.Blur.INNER));//设置画笔遮罩滤镜 ,传入度数和样式
canvas.drawLine(100,100,W-100,100,mPaint);
canvas.restoreToCount(sc);
sc = canvas.saveLayer(0, H*4, W+300, H*4+500, null);
canvas.translate(0, H*4);
canvas.drawText("图片加阴影", 100,50,labelP);
Bitmap mBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.girl);
// 获取位图的Alpha通道图
Bitmap shadowBitmap = mBitmap.extractAlpha();
mPaint.setColor(Color.DKGRAY);
// 设置画笔遮罩滤镜 ,传入度数和样式
mPaint.setMaskFilter(new BlurMaskFilter(10, BlurMaskFilter.Blur.NORMAL));
// 先绘制阴影
canvas.drawBitmap(shadowBitmap, 100, 100, mPaint);
// 画原图
canvas.drawBitmap(mBitmap, 100, 100, null);
canvas.restoreToCount(sc);
5f6e4219e2cf324181dd9a238382b854.png
测量文本宽度
private void drawMeasureText(Canvas canvas) {
mPaint.reset();
mPaint.setColor(Color.BLACK);
String str = "测试文本的长度:";
Rect rect = new Rect();
float size = 0;
mPaint.setTextSize(10);
mPaint.getTextBounds(str, 0, str.length(), rect); //测量文本大小，将文本大小信息存放在rect中
size = mPaint.measureText(str);//获取文本的宽
canvas.drawText(str + size, 100, 100, mPaint);
mPaint.setTextSize(20);
mPaint.getTextBounds(str, 0, str.length(), rect); //测量文本大小，将文本大小信息存放在rect中
size = mPaint.measureText(str);//获取文本的宽
canvas.drawText(str + size, 100, 120, mPaint);
mPaint.setTextSize(30);
mPaint.getTextBounds(str, 0, str.length(), rect); //测量文本大小，将文本大小信息存放在rect中
size = mPaint.measureText(str);//获取文本的宽
canvas.drawText(str + size, 100, 150, mPaint);
mPaint.setTextSize(40);
mPaint.getTextBounds(str, 0, str.length(), rect); //测量文本大小，将文本大小信息存放在rect中
size = mPaint.measureText(str);//获取文本的宽
canvas.drawText(str + size, 100, 190, mPaint);
mPaint.setTextSize(50);
mPaint.getTextBounds(str, 0, str.length(), rect); //测量文本大小，将文本大小信息存放在rect中
size = mPaint.measureText(str);//获取文本的宽
canvas.drawText(str + size, 100, 240, mPaint);
postInvalidate();
invalidate();
}