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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