Paint介绍

Paint介绍

---

1. Paint.Cap

注意：Cap一般作用于边界处，不作用连接处
BUTT (0),//无线帽
ROUND (1),//圆形线帽
SQUARE (2);//方形线帽

![Cap图片]!

        paint.setColor(Color.RED);        paint.setStrokeWidth(60);        paint.setStrokeCap(Paint.Cap.BUTT);        canvas.drawLine(100, 100, 600, 100, paint);        paint.setStrokeCap(Paint.Cap.ROUND);        canvas.drawLine(100, 300, 600, 300, paint);        paint.setStrokeCap(Paint.Cap.SQUARE);        canvas.drawLine(100, 500, 600, 500, paint);

2. Paint.Join

MITER   (0),//有尖角的连接ROUND   (1),//圆弧连接BEVEL   (2);//直线连接

        paint.setStrokeWidth(60);        paint.setColor(Color.YELLOW);        paint.setStyle(Paint.Style.STROKE);        paint.setStrokeJoin(Paint.Join.MITER);        canvas.drawRect(new RectF(100,100,300,300),paint);        paint.setStrokeJoin(Paint.Join.BEVEL);        canvas.drawRect(400, 100, 600, 300, paint);        paint.setStrokeJoin(Paint.Join.ROUND);        canvas.drawRect(100, 400, 300, 600, paint);

3. Paint.Align

        paint.setStrokeWidth(5);        paint.setTextSize(30);        paint.setShadowLayer(10,10,10,Color.RED);        paint.setTextAlign(Paint.Align.LEFT);        canvas.drawText("Paint.Align.LEFT",400,100,paint);        paint.setShadowLayer(10,10,10,Color.RED);        paint.setTextAlign(Paint.Align.CENTER);        canvas.drawText("Paint.Align.CENTER",400,300,paint);        paint.setShadowLayer(10,10,10,Color.RED);        paint.setTextAlign(Paint.Align.RIGHT);        canvas.drawText("Paint.Align.RIGHT",400,500,paint);        canvas.drawLine(400,0,400,800,paint);

4. Paint.Style
Paint.Style.FILL：填充内部
Paint.Style.STROKE 描边
Paint.Style.FILL_AND_STROKE ：填充内部和描边

  paint.setStrokeWidth(20);        paint.setStyle(Paint.Style.FILL);        canvas.drawRect(new RectF(100,100,300,300),paint);        canvas.drawText("Paint.Style.FILL",350,200,paint);        paint.setStyle(Paint.Style.STROKE);        canvas.drawRect(new RectF(100,350,300,550),paint);        canvas.drawText("Paint.Style.STROKE",350,400,paint);        paint.setStyle(Paint.Style.FILL_AND_STROKE);        canvas.drawRect(new RectF(100,600,300,800),paint);        canvas.drawRect(new RectF(100,350,300,550),paint);        canvas.drawText("Paint.Style.FILL_AND_STROKE",350,700,paint);

5.Paint.FontMetrics

ascent = ascent线的y坐标 - baseline线的y坐标；//负数

descent = descent线的y坐标 - baseline线的y坐标；//正数

top = top线的y坐标 - baseline线的y坐标；//负数

bottom = bottom线的y坐标 - baseline线的y坐标；//正数

leading = top线的y坐标 - ascent线的y坐标；//负数

  paint.setStrokeWidth(1);        paint.setTextSize(50);        Paint.FontMetrics fontMetrics = paint.getFontMetrics();        float ascent = fontMetrics.ascent +300;        float descent = fontMetrics.descent+300;        float top = fontMetrics.top + 300;        float bottom = fontMetrics.bottom + 300;        canvas.drawText("abcdefg",300,300,paint);        paint.setTextSize(20);        canvas.drawLine(300,ascent,600,ascent,paint);        canvas.drawText("ascent=top",650,ascent,paint);        canvas.drawLine(300,descent,600,descent,paint);        canvas.drawText("descent=bottom",650,descent,paint);        canvas.drawLine(300,-(bottom-top)/2+bottom,600,-(bottom-top)/2+bottom,paint);//中线        canvas.drawText("center",650,-(bottom-top)/2+bottom,paint);

6. Paint方法介绍
reset() //重置Paint。

 setFlags(int flags)//设置一些标志，比如抗锯齿，下划线等等。 setDither(boolean dither)//设置是否抖动，如果不设置感觉就会有一些僵硬的线条，如果设置图像就会看的更柔和一些setLinearText(boolean linearText) //这个是文本缓存，设置线性文本，如果设置为true就不需要缓存

setSubpixelText(boolean subpixelText)//设置亚像素，是对文本的一种优化设置，可以让文字看起来更加清晰明显

setUnderlineText(boolean underlineText)//设置文本的下划线

setStrikeThruText(boolean strikeThruText)//设置文本的删除线

setFakeBoldText(boolean fakeBoldText)//设置文本粗体setFilterBitmap(boolean filter)//对位图进行滤波处理，如果该项设置为true，则图像在动画进行中会滤掉对Bitmap图像的优化操作，加快显示 setStrokeMiter(float miter)//当style为Stroke或StrokeAndFill时设置连接处的倾斜度，这个值必须大于1,锐角越接近0，miter值得上限越大，也就是<=MITERmax时都有倾斜

   paint.setStrokeWidth(30);        paint.setStyle(Paint.Style.STROKE);        paint.setStrokeMiter((float)3);        Path path = new Path();        path.moveTo(0,30);        path.lineTo(400,250);        path.lineTo(300,30);        canvas.drawPath(path,paint);        path.reset();        paint.setStrokeMiter((float)2);        path.moveTo(300,300);        path.lineTo(500,300);        path.lineTo(400,550);        canvas.drawPath(path,paint);

setShader(Shader shader)//设置着色器，用来给图像着色的，绘制出各种渐变效果，有BitmapShader，ComposeShader，LinearGradient，RadialGradient，SweepGradient几种

BitmapShader
构造方法：BitmapShader (Bitmap bitmap, Shader.TileMode tileX, Shader.TileMode tileY)

第一个参数：要处理的bitmap对象
第二个参数：在X轴处理的效果，Shader.TileMode里有三种模式：CLAMP、MIRROR和REPETA
第三个参数：在Y轴处理的效果，Shader.TileMode里有三种模式：CLAMP、MIRROR和REPETA

Shader.TileMode.CLAMP会将边缘的一个像素进行拉伸、扩展

拉伸后效果

Shader.TileMode.MIRROR模式作用是镜像

Shader.TileMode.REPEAT
这个应该是重复模式，和镜像十分类似，但是不是翻转复制，而是平移复制。(x轴方向平移复制，y轴方向镜像复制)

LinearGradient
构造函数：public LinearGradient (float x0, float y0, float x1, float y1, int color0, int color1, Shader.TileMode tile)
（x0，y0）表示渐变的起点坐标而（x1，y1）则表示渐变的终点坐标，这两点都是相对于屏幕坐标系而言的，而color0和color1则表示起点的颜色和终点的颜色，TileMode和上面讲的完全一致。
[（x0,y0,x1,y1)范围为三角形(x0,y0)(2x1-x0,y0)(x0,2y1-y0)自己想的）]

 paint.setShader(new LinearGradient(0,0,100,100,Color.RED,Color.YELLOW, Shader.TileMode.MIRROR));        canvas.drawRect(new RectF(0,0,400,400),paint);

另一个构造方法：public LinearGradient (float x0, float y0, float x1, float y1, int[] colors, float[] positions, Shader.TileMode tile)
colors和positions都是数组,positions可以为空，为空时系统自动调整，颜色变化是线性的，在pos[i+1]-pos[i]位置线性到达color[i+1]

        paint.setShader(new LinearGradient(0,0,200,200,new int[]{Color.RED,Color.BLUE,Color.YELLOW},        new float[]{0F,0.4F,1F}, Shader.TileMode.REPEAT));        canvas.drawRect(new RectF(0,0,400,400),paint);

绘制图片阴影

 canvas.drawColor(Color.GRAY);        int x = 200, y = 200;        // 获取源图        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.apic);        // 实例化一个矩阵对象        Matrix matrix = new Matrix();        matrix.setScale(1F,-1F);//第一个参数表示x缩放,第二参数表示y的缩放        Bitmap refBitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);        // 绘制好原图        canvas.drawBitmap(bitmap, x, y, null);        // 保存图层。ALL_SAVE_FLAG保存所有信息，包括裁剪区域和矩阵变化，restore()返回最上一层        int sc = canvas.saveLayer(x, y + bitmap.getHeight(), x + bitmap.getWidth(), y + bitmap.getHeight() * 2, null, Canvas.ALL_SAVE_FLAG);        // 绘制倒影图片，绘制的区域紧贴原图的底部        canvas.drawBitmap(refBitmap, x, y + bitmap.getHeight(),null);        // 设置好混合模式        paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.DST_IN));//显示src和des重叠的src部分        paint.setShader(new LinearGradient(x, y + bitmap.getHeight(),x, y + bitmap.getHeight() +                bitmap.getHeight() / 4,Color.BLACK, Color.TRANSPARENT, Shader.TileMode.CLAMP));        // 画一个矩形区域，作为目标图片，用来做混合模式        canvas.drawRect(x, y + bitmap.getHeight(), x + refBitmap.getWidth(), y + bitmap.getHeight() * 2, paint);        paint.reset();        canvas.restoreToCount(sc);//restoreToCount()返回到sc层，类似于堆栈一个一个取出来

为了看清效果，我把倒影图和原图大小变得不一样，倒影图比原图小20px;

SweepGradient
它的意思是梯度渐变，也称之为扫描式渐变，因为其效果有点类似雷达的扫描效果
构造方法:SweepGradient(float cx, float cy, int color0, int color1)

  paint.setShader(new SweepGradient(100,100,Color.RED,Color.YELLOW));      canvas.drawRect(new RectF(0,0,200,200),paint);

效果：

构造方法：
SweepGradient(float cx, float cy, int[] colors, float[] positions)

 paint.setShader(new SweepGradient(100,100,new int[]{Color.RED,Color.BLUE,Color.TRANSPARENT},new float[]{0F,0.4F,1.0F}));//Color.RED->Color.BLUE是从0->0.4,position是相对这个区域的，postion可以为null      canvas.drawRect(new RectF(0,0,200,200),paint);

效果：

RadialGradient
径向渐变，径向渐变说的简单点就是个圆形中心向四周渐变的效果
构造方法：
RadialGradient (float centerX, float centerY, float radius, int centerColor, int edgeColor, Shader.TileMode tileMode)

RadialGradient (float centerX, float centerY, float radius, int[] colors, float[] stops, Shader.TileMode tileMode)

  paint.setShader(new RadialGradient(100,100,100,Color.RED,Color.BLUE, Shader.TileMode.CLAMP));      canvas.drawRect(new RectF(0,0,200,200),paint);

效果：

       paint.setShader(new RadialGradient(100,100,100,new int[]{Color.RED,Color.BLUE,Color.YELLOW}, new float[]{0,0.5f,1.0f},Shader.TileMode.CLAMP));      canvas.drawRect(new RectF(0,0,200,200),paint);

效果：

ComposeShader
构造方法：ComposeShader (Shader shaderA, Shader shaderB, Xfermode mode)
ComposeShader (Shader shaderA, Shader shaderB, PorterDuff.Mode mode)
一般是一个BitmapShader+一个XXGradient;

Shader shader = new BitmapShader(BitmapFactory.decodeResource(getResources(),R.drawable.apic), Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);        Shader shader01 = new SweepGradient(200,200,new int[]{Color.YELLOW,Color.RED,Color.BLUE},new float[]{0.25f,0.5f,0.75f});       paint.setShader(new ComposeShader(shader01, shader, PorterDuff.Mode.MULTIPLY));        canvas.drawRect(0, 0, 400, 400, paint);

效果：

Shader And Matrix

 Shader shader = new BitmapShader(BitmapFactory.decodeResource(getResources(),R.drawable.apic), Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);        Matrix matrix = new Matrix();        matrix.setTranslate(100,100);        shader.setLocalMatrix(matrix);        paint.setShader(shader);        canvas.drawRect(0, 0, 400, 400, paint);

效果：

 Shader shader = new BitmapShader(BitmapFactory.decodeResource(getResources(),R.drawable.apic), Shader.TileMode.CLAMP, Shader.TileMode.CLAMP);        Matrix matrix = new Matrix();        matrix.postTranslate(200,100);        matrix.preRotate(45);        shader.setLocalMatrix(matrix);        paint.setShader(shader);        canvas.drawRect(0, 0, 400, 400, paint);

效果：

setColorFilter(ColorFilter filter)//设置画笔颜色过滤器，有ColorMatrixColorFilter，LightingColorFilter，PorterDuffColorFilter几种

先介绍ColorMatrix:
颜色矩阵的计算：

ColorMatrix函数介绍：
色调调节setRotate(int axis, float degrees)



效果叠加
preConcat(ColorMatrix prematrix)和postConcat(ColorMatrix postmatrix)两个方法分别是将目标效果矩阵放在本矩阵之前和放在本矩阵之后，由于矩阵的乘法一般不满足交换律，因此前后关系会对效果有不同的影响。

ColorMatrixColorFilter

reset();        Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.apic);        canvas.drawBitmap(bitmap,100,0,paint);        paint.setColorFilter(new ColorMatrixColorFilter(a));        canvas.drawBitmap(bitmap,100,500,paint);        ColorMatrix colorMatrix = new ColorMatrix();        colorMatrix.setSaturation(0);        paint.setColorFilter(new ColorMatrixColorFilter(colorMatrix));        canvas.drawBitmap(bitmap,100,1000,paint);

LightingColorFilter

 Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.apic);        canvas.drawBitmap(bitmap,100,0,paint);        paint.setColorFilter(new LightingColorFilter(0x888888,0x000000));        canvas.drawBitmap(bitmap,100,500,paint);        paint.setColorFilter(new LightingColorFilter(0x888888,0x555555));        canvas.drawBitmap(bitmap,100,1000,paint);

PorterDuffColorFilter
构造方法：public PorterDuffColorFilter(int srcColor, PorterDuff.Mode mode)

  Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.drawable.apic);        paint.setColorFilter(new PorterDuffColorFilter(Color.RED, PorterDuff.Mode.MULTIPLY));        canvas.drawBitmap(bitmap,100,0,paint);

PorterDuff.Mode种类

setPathEffect(PathEffect effect)//设置绘制路径的效果，有ComposePathEffect，CornerPathEffect，DashPathEffect，DiscretePathEffect，PathDashPathEffect，SumPathEffect几种

CornerPathEffect：
构造函数：CornerPathEffect(float radius）
参数radius代表了半径，这里的半径就是塞进拐角处圆形的半径，即是用多大半径的圆弧来替换这个拐角。

 Path path = new Path();        path.moveTo(100,400);        path.rLineTo(400,400);        path.rLineTo(100,-400);        paint.setStyle(Paint.Style.STROKE);        paint.setColor(Color.BLUE);        paint.setPathEffect(new CornerPathEffect(100));        canvas.drawPath(path,paint);

DashPathEffect
构造函数：DashPathEffect(float intervals[], float phase)
其中intervals是间隔，他是一个数组，其中数值必须为偶数，2个为一对，必须成对出现，一对中的第一个代表了线段长度(为0则绘制)，第二个代表了空白长度（为0则不留空白）这里可以看出来其实线段2中是由两对数值组成的值如下：

float[] intervals = {100,20,200,50};
参数中phase（假设是80）代表了相位表示从intervals 80开始，也就是先绘制100-80=20的实线，然后绘制20空白，让后绘制200实线，然后绘制50空白，接着绘制100实线，以此类推

float intervals[] = {100,30,200,50};        paint.setStyle(Paint.Style.STROKE);        paint.setColor(Color.BLUE);        paint.setPathEffect(new DashPathEffect(intervals,0));        Path path = new Path();        path.moveTo(100,500);        path.rLineTo(500,500);        path.rLineTo(100,-500);        canvas.drawPath(path,paint);        path.reset();        path.moveTo(100,900);        path.rLineTo(500,500);        path.rLineTo(500,-500);        canvas.drawPath(path,paint);

DiscretePathEffect

构造函数： DiscretePathEffect(float segmentLength, float deviation)
这里有两个参数，第一个segmentLength字面上看就是段长，deviation代表偏差值。
参数一：指定了原始线段被切分成多长的线段，比如原始线段长度为100.段长设置为20，那么就被切成了5段。
参数二：指定了切割后的小线段于原始位置的偏离距离。

  paint.setStyle(Paint.Style.STROKE);        paint.setColor(Color.BLUE);        paint.setPathEffect(new DiscretePathEffect(10,10));        Path path = new Path();        path.moveTo(100,500);        path.rLineTo(500,500);        path.rLineTo(100,-500);        canvas.drawPath(path,paint);        paint.setPathEffect(new DiscretePathEffect(10,20));        path.reset();        path.moveTo(100,900);        path.rLineTo(500,500);        path.rLineTo(500,-500);        canvas.drawPath(path,paint);

PathDashPathEffect
PathDashPathEffect(Path shape, float advance, float phase,Style style)
shape：代表了绘制的形状，这里是一个三角形
advace：绘制位移，上一次绘制这个三角形，和下一次绘制三角形起点之间的位移
phase：相位，于之前讲解的相同
style：风格，这里后面三条线就是因为这个参数引起的不同

Style是一个枚举，值如下
TRANSLATE(0), //平移
ROTATE(1), //旋转
MORPH(2); //变形

     Path pathDash = new Path();        pathDash.rLineTo(10,10);        pathDash.rLineTo(10,-10);        pathDash.close();        paint.setStyle(Paint.Style.STROKE);        paint.setColor(Color.BLUE);        paint.setPathEffect(new PathDashPathEffect(pathDash,35,0, PathDashPathEffect.Style.TRANSLATE));        Path path = new Path();        path.moveTo(100,500);        path.rLineTo(500,500);        path.rLineTo(100,-500);        canvas.drawPath(path,paint);        paint.setPathEffect(new PathDashPathEffect(pathDash,35,0, PathDashPathEffect.Style.ROTATE));        path.reset();        path.moveTo(100,900);        path.rLineTo(500,500);        path.rLineTo(500,-500);        canvas.drawPath(path,paint);

ComposePathEffect和SumPathEffect

 float intervals[] = {100,30};        paint.setStyle(Paint.Style.STROKE);        paint.setColor(Color.BLUE);        paint.setPathEffect(new ComposePathEffect(new DashPathEffect(intervals,0),new CornerPathEffect(100)));        Path path = new Path();        path.moveTo(100,500);        path.rLineTo(500,500);        path.rLineTo(100,-500);        canvas.drawPath(path,paint);        paint.setPathEffect(new SumPathEffect(new DashPathEffect(intervals,0),new CornerPathEffect(100)));        path.reset();        path.moveTo(100,900);        path.rLineTo(500,500);        path.rLineTo(500,-500);        canvas.drawPath(path,paint);

线段1是compose，线段2是sum，看图就已经非常明显，sum只是简单的叠加效果，而compose是组合效果。

setMaskFilter(MaskFilter maskfilter)//对图像进行一定的处理，实现滤镜的效果，如滤化，立体等,有BlurMaskFilter，EmbossMaskFilter几种
BlurMaskFilter：
构造函数：BlurMaskFilter(float radius, BlurMaskFilter.Blur style)

第一个参数：radius很容易理解，值越大我们的阴影越扩散，用过PS的人会很容易理解，其实就是阴影范围。
第二个参数：style表示的是模糊的类型，有SOLID，NORMAL,OUTER和INNER

 setLayerType(LAYER_TYPE_SOFTWARE, null);//关闭硬件加速  paint.setColor(Color.BLUE);        paint.setMaskFilter(new BlurMaskFilter(30, BlurMaskFilter.Blur.SOLID));        canvas.drawRect(new RectF(100,100,500,500),paint);        paint.setMaskFilter(new BlurMaskFilter(30, BlurMaskFilter.Blur.NORMAL));        canvas.drawRect(new RectF(100,600,500,1000),paint);        paint.setMaskFilter(new BlurMaskFilter(30, BlurMaskFilter.Blur.OUTER));        canvas.drawRect(new RectF(600,100,1000,500),paint);        paint.setMaskFilter(new BlurMaskFilter(30, BlurMaskFilter.Blur.INNER));        canvas.drawRect(new RectF(600,600,1000,1000),paint);