Android ApiDemo 笔记（二）Graphics和View

package com.example.android.apis.graphics;

23.TextAlign：

设置Path路径，贝赛尔曲线

1:  //设置Path路径

2:      private static void makePath(Path p) {

3:          p.moveTo(10, 0);

4:          p.cubicTo(100, -50, 200, 50, 300, 0);//贝赛尔曲线

5:      }

//mPos存的是字符串中每个字符的位置坐标

 1:  private float[] buildTextPositions(String text, float y, Paint paint) {

 2:          float[] widths = new float[text.length()];

 3:          // initially get the widths for each char

 4:          int n = paint.getTextWidths(text, widths);

 5:          // now popuplate the array, interleaving spaces for the Y values X值为字符的宽

 6:          float[] pos = new float[n * 2];

 7:          float accumulatedX = 0;

 8:          for (int i = 0; i < n; i++) {

 9:              pos[i * 2 + 0] = accumulatedX;

10:              pos[i * 2 + 1] = y;

11:              accumulatedX += widths[i];

12:          }

13:          return pos;

14:      }

onDraw（）方法中：

画

1:  p.setColor(0x80FF0000);

2:              canvas.drawLine(x, y, x, y + DY * 3, p);//(x,y)为基准线

3:              p.setColor(Color.BLACK);

4:  

5:              canvas.translate(0, DY);

6:              p.setTextAlign(Paint.Align.LEFT);

7:              canvas.drawText(TEXT_L, x, y, p);//以（x,y）点Paint.Align.LEFT，画

画

1:  p.setColor(0xBB00FF00);

2:      for (int i = 0; i < pos.length / 2; i++) {

3:          canvas.drawLine(pos[i * 2 + 0], pos[i * 2 + 1] - DY, pos[i * 2 + 0],

4:              pos[i * 2 + 1] + DY * 2, p);

5:      }

6:      p.setColor(Color.BLACK);

7:  

8:      p.setTextAlign(Paint.Align.LEFT);

9:      canvas.drawPosText(POSTEXT, pos, p);

画

 1:  canvas.drawPath(mPath, mPathPaint);

 2:              p.setTextAlign(Paint.Align.LEFT);

 3:              canvas.drawTextOnPath(TEXTONPATH, mPath, 0, 0, p);

 4:  

 5:              canvas.translate(0, DY * 1.5f);

 6:              canvas.drawPath(mPath, mPathPaint);

 7:              p.setTextAlign(Paint.Align.CENTER);

 8:              canvas.drawTextOnPath(TEXTONPATH, mPath, 0, 0, p);

 9:  

10:              canvas.translate(0, DY * 1.5f);

11:              canvas.drawPath(mPath, mPathPaint);

12:              p.setTextAlign(Paint.Align.RIGHT);

13:              canvas.drawTextOnPath(TEXTONPATH, mPath, 0, 0, p);

24.Typefaces：

获得assets/fonts下的字体

1:  mFace = Typeface.createFromAsset(getContext().getAssets(),

2:              "fonts/samplefont.ttf");

onDraw()方法

1:  @Override

2:          protected void onDraw(Canvas canvas) {

3:              canvas.drawColor(Color.WHITE);

4:  

5:              mPaint.setTypeface(null);

6:              canvas.drawText("Default", 10, 100, mPaint);

7:              mPaint.setTypeface(mFace);

8:              canvas.drawText("Custom", 10, 200, mPaint);

9:          }

25.UnicodeChart：（没看）

26.Vertices:(没看) 触摸一下，图片走形

27.Xfermodes：

圆形画法：

1:  static Bitmap makeDst(int w, int h) {

2:          Bitmap bm = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);

3:          Canvas c = new Canvas(bm);

4:          Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);

5:          p.setColor(0xFFFFCC44);

6:          c.drawOval(new RectF(0, 0, w * 3 / 4, h * 3 / 4), p);

7:          return bm;

8:      }

正方形的画法：

1:  static Bitmap makeSrc(int w, int h) {

2:          Bitmap bm = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);

3:          Canvas c = new Canvas(bm);

4:          Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);

5:  

6:          p.setColor(0xFF66AAFF);

7:          c.drawRect(w / 3, h / 3, w * 19 / 20, h * 19 / 20, p);

8:          return bm;

9:      }

背景马塞克画法：

1:  Bitmap bm = Bitmap.createBitmap(new int[] { 0xFFFFFFFF, 0xFFCCCCCC,

2:                  0xFFCCCCCC, 0xFFFFFFFF }, 2, 2, Bitmap.Config.RGB_565);

3:              mBG = new BitmapShader(bm, Shader.TileMode.REPEAT, Shader.TileMode.REPEAT);

4:              Matrix m = new Matrix();

5:              m.setScale(6, 6);// 放大6倍

6:              mBG.setLocalMatrix(m);

Xfermode数组：

 1:  private static final Xfermode[] sModes = {

 2:              new PorterDuffXfermode(PorterDuff.Mode.CLEAR),

 3:              new PorterDuffXfermode(PorterDuff.Mode.SRC),

 4:              new PorterDuffXfermode(PorterDuff.Mode.DST),

 5:              new PorterDuffXfermode(PorterDuff.Mode.SRC_OVER),

 6:              new PorterDuffXfermode(PorterDuff.Mode.DST_OVER),

 7:              new PorterDuffXfermode(PorterDuff.Mode.SRC_IN),

 8:              new PorterDuffXfermode(PorterDuff.Mode.DST_IN),

 9:              new PorterDuffXfermode(PorterDuff.Mode.SRC_OUT),

10:              new PorterDuffXfermode(PorterDuff.Mode.DST_OUT),

11:              new PorterDuffXfermode(PorterDuff.Mode.SRC_ATOP),

12:              new PorterDuffXfermode(PorterDuff.Mode.DST_ATOP),

13:              new PorterDuffXfermode(PorterDuff.Mode.XOR),

14:              new PorterDuffXfermode(PorterDuff.Mode.DARKEN),

15:              new PorterDuffXfermode(PorterDuff.Mode.LIGHTEN),

16:              new PorterDuffXfermode(PorterDuff.Mode.MULTIPLY),

17:              new PorterDuffXfermode(PorterDuff.Mode.SCREEN) };

onDraw()方法：

 1:  @Override

 2:          protected void onDraw(Canvas canvas) {

 3:              canvas.drawColor(Color.WHITE);

 4:  

 5:              Paint labelP = new Paint(Paint.ANTI_ALIAS_FLAG);

 6:              labelP.setTextAlign(Paint.Align.CENTER);

 7:  

 8:              Paint paint = new Paint();

 9:              paint.setFilterBitmap(false);

10:  

11:              canvas.translate(15, 35);

12:  

13:              int x = 0;

14:              int y = 0;

15:              for (int i = 0; i < sModes.length; i++) {

16:                  // draw the border

17:                  paint.setStyle(Paint.Style.STROKE);

18:                  paint.setShader(null);// Pass null to clear any previous shader

19:                  canvas.drawRect(x - 0.5f, y - 0.5f, x + W + 0.5f, y + H + 0.5f, paint);

20:  

21:                  // draw the checker-board pattern

22:                  paint.setStyle(Paint.Style.FILL);

23:                  paint.setShader(mBG);

24:                  canvas.drawRect(x, y, x + W, y + H, paint);

25:  

26:                  // draw the src/dst example into our offscreen bitmap

27:                  int sc = canvas.saveLayer(x, y, x + W, y + H, null,

28:                      Canvas.MATRIX_SAVE_FLAG | Canvas.CLIP_SAVE_FLAG

29:                          | Canvas.HAS_ALPHA_LAYER_SAVE_FLAG

30:                          | Canvas.FULL_COLOR_LAYER_SAVE_FLAG

31:                          | Canvas.CLIP_TO_LAYER_SAVE_FLAG);

32:                  // canvas.save();

33:                  canvas.translate(x, y);

34:                  canvas.drawBitmap(mDstB, 0, 0, paint);

35:                  paint.setXfermode(sModes[i]);

36:                  canvas.drawBitmap(mSrcB, 0, 0, paint);

padding-bottom: 0px !important; line-height: 18px; background-color: #f7f7ff !important; margin: 0em; padding-left: 12px !important; padding-right: 0px !important; color

  


  

    
    
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2010-05-18 22:33
      
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