安卓自定义视图 - 手写签名的实现

来源：互联网发布：mac 图标大小编辑：程序博客网时间：2024/04/29 23:09
public class LinePathView extends View {    private Context mContext;    /**     * 笔画X坐标起点     */    private float mX;    /**     * 笔画Y坐标起点     */    private float mY;    /**     * 手写画笔     */    private final Paint mGesturePaint = new Paint();    /**     * 路径     */    private final Path mPath = new Path();    /**     * 签名画笔     */    private Canvas cacheCanvas;    /**     * 签名画布     */    private Bitmap cachebBitmap;    /**     * 是否已经签名     */    private boolean isTouched = false;    /**     * 画笔宽度 px；     */    private int mPaintWidth = 10;    /**     * 前景色     */    private int mPenColor = Color.BLACK;    /**     * 背景色（指最终签名结果文件的背景颜色，默认为透明色）     */    private int mBackColor=Color.TRANSPARENT;    public LinePathView(Context context) {        super(context);        init(context);    }    public LinePathView(Context context, AttributeSet attrs) {        super(context, attrs);        init(context);    }    public LinePathView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        init(context);    }    public void init(Context context) {        this.mContext = context;        //设置抗锯齿        mGesturePaint.setAntiAlias(true);        //设置签名笔画样式        mGesturePaint.setStyle(Style.STROKE);        //设置笔画宽度        mGesturePaint.setStrokeWidth(mPaintWidth);        //设置签名颜色        mGesturePaint.setColor(mPenColor);    }    @Override    protected void onSizeChanged(int w, int h, int oldw, int oldh) {        super.onSizeChanged(w, h, oldw, oldh);        //创建跟view一样大的bitmap，用来保存签名        cachebBitmap = Bitmap.createBitmap(getWidth(), getHeight(), Config.ARGB_8888);        cacheCanvas = new Canvas(cachebBitmap);        cacheCanvas.drawColor(mBackColor);        isTouched=false;    }    @Override    public boolean onTouchEvent(MotionEvent event) {        switch (event.getAction()) {            case MotionEvent.ACTION_DOWN:                touchDown(event);                break;            case MotionEvent.ACTION_MOVE:                isTouched = true;                touchMove(event);                break;            case MotionEvent.ACTION_UP:            //将路径画到bitmap中，即一次笔画完成才去更新bitmap，而手势轨迹是实时显示在画板上的。                cacheCanvas.drawPath(mPath, mGesturePaint);                mPath.reset();                break;        }        // 更新绘制        invalidate();        return true;    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        //画此次笔画之前的签名        canvas.drawBitmap(cachebBitmap, 0, 0, mGesturePaint);        // 通过画布绘制多点形成的图形        canvas.drawPath(mPath, mGesturePaint);    }    // 手指点下屏幕时调用    private void touchDown(MotionEvent event) {        // 重置绘制路线        mPath.reset();        float x = event.getX();        float y = event.getY();        mX = x;        mY = y;        // mPath绘制的绘制起点        mPath.moveTo(x, y);    }    // 手指在屏幕上滑动时调用    private void touchMove(MotionEvent event) {        final float x = event.getX();        final float y = event.getY();        final float previousX = mX;        final float previousY = mY;        final float dx = Math.abs(x - previousX);        final float dy = Math.abs(y - previousY);        // 两点之间的距离大于等于3时，生成贝塞尔绘制曲线        if (dx >= 3 || dy >= 3) {            // 设置贝塞尔曲线的操作点为起点和终点的一半            float cX = (x + previousX) / 2;            float cY = (y + previousY) / 2;            // 二次贝塞尔，实现平滑曲线；previousX, previousY为操作点，cX, cY为终点            mPath.quadTo(previousX, previousY, cX, cY);            // 第二次执行时，第一次结束调用的坐标值将作为第二次调用的初始坐标值            mX = x;            mY = y;        }    }    /**     * 清除画板     */    public void clear() {        if (cacheCanvas != null) {            isTouched = false;            //更新画板信息            mGesturePaint.setColor(mPenColor);            cacheCanvas.drawColor(mBackColor,PorterDuff.Mode.CLEAR);            mGesturePaint.setColor(mPenColor);            invalidate();        }    }    /**     * 保存画板     * @param path 保存到路径     */    public void save(String path)  throws IOException {        save(path, false, 0);    }    /**     * 保存画板     * @param path       保存到路径     * @param clearBlank 是否清除边缘空白区域     * @param blank  要保留的边缘空白距离     */    public void save(String path, boolean clearBlank, int blank) throws IOException {        Bitmap bitmap=cachebBitmap;        //BitmapUtil.createScaledBitmapByHeight(srcBitmap, 300);//  压缩图片        if (clearBlank) {            bitmap = clearBlank(bitmap, blank);        }        ByteArrayOutputStream bos = new ByteArrayOutputStream();        bitmap.compress(Bitmap.CompressFormat.PNG, 100, bos);        byte[] buffer = bos.toByteArray();        if (buffer != null) {                File file = new File(path);                if (file.exists()) {                    file.delete();                }                OutputStream outputStream = new FileOutputStream(file);                outputStream.write(buffer);                outputStream.close();        }    }    /**     * 获取画板的bitmap     * @return     */    public Bitmap getBitMap()    {        setDrawingCacheEnabled(true);        buildDrawingCache();        Bitmap bitmap=getDrawingCache();        setDrawingCacheEnabled(false);        return bitmap;    }    /**     * 逐行扫描 清楚边界空白。     *     * @param bp     * @param blank 边距留多少个像素     * @return     */    private Bitmap clearBlank(Bitmap bp, int blank) {        int HEIGHT = bp.getHeight();        int WIDTH = bp.getWidth();        int top = 0, left = 0, right = 0, bottom = 0;        int[] pixs = new int[WIDTH];        boolean isStop;        //扫描上边距不等于背景颜色的第一个点        for (int y = 0; y < HEIGHT; y++) {            bp.getPixels(pixs, 0, WIDTH, 0, y, WIDTH, 1);            isStop = false;            for (int pix : pixs) {                if (pix != mBackColor) {                    top = y;                    isStop = true;                    break;                }            }            if (isStop) {                break;            }        }        //扫描下边距不等于背景颜色的第一个点        for (int y = HEIGHT - 1; y >= 0; y--) {            bp.getPixels(pixs, 0, WIDTH, 0, y, WIDTH, 1);            isStop = false;            for (int pix : pixs) {                if (pix != mBackColor) {                    bottom = y;                    isStop = true;                    break;                }            }            if (isStop) {                break;            }        }        pixs = new int[HEIGHT];        //扫描左边距不等于背景颜色的第一个点        for (int x = 0; x < WIDTH; x++) {            bp.getPixels(pixs, 0, 1, x, 0, 1, HEIGHT);            isStop = false;            for (int pix : pixs) {                if (pix != mBackColor) {                    left = x;                    isStop = true;                    break;                }            }            if (isStop) {                break;            }        }        //扫描右边距不等于背景颜色的第一个点        for (int x = WIDTH - 1; x > 0; x--) {            bp.getPixels(pixs, 0, 1, x, 0, 1, HEIGHT);            isStop = false;            for (int pix : pixs) {                if (pix != mBackColor) {                    right = x;                    isStop = true;                    break;                }            }            if (isStop) {                break;            }        }        if (blank < 0) {            blank = 0;        }        //计算加上保留空白距离之后的图像大小        left = left - blank > 0 ? left - blank : 0;        top = top - blank > 0 ? top - blank : 0;        right = right + blank > WIDTH - 1 ? WIDTH - 1 : right + blank;        bottom = bottom + blank > HEIGHT - 1 ? HEIGHT - 1 : bottom + blank;        return Bitmap.createBitmap(bp, left, top, right - left, bottom - top);    }    /**     * 设置画笔宽度 默认宽度为10px     *     * @param mPaintWidth     */    public void setPaintWidth(int mPaintWidth) {        mPaintWidth = mPaintWidth > 0 ? mPaintWidth : 10;        this.mPaintWidth = mPaintWidth;        mGesturePaint.setStrokeWidth(mPaintWidth);    }    public void setBackColor(@ColorInt int backColor)    {        mBackColor=backColor;    }    /**     * 设置画笔颜色     *     * @param mPenColor     */    public void setPenColor(int mPenColor) {        this.mPenColor = mPenColor;        mGesturePaint.setColor(mPenColor);    }    /**     * 是否有签名     *     * @return     */    public boolean getTouched() {        return isTouched;    }}
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