本文介绍了安卓：用贝塞尔数字签名的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我试图用贝塞尔作为展现在上面image.when我抚摸两队战平的数字签名，并尝试画线则结果为点线，但没有得到络绎不绝。简单的签名使用简单的签名但我想创造更多的使用贝塞尔触摸pressure平滑的曲线。试图与此链接
I am trying two draw digital signature using Bezier as show in above image.when i touch and try to draw line then the result is dot line but not getting continuous line.Simple signature done by using simple signaturebut I want to create more a smooth curve using Bezier with touch pressure.tried with this link
SignatureViewDemo.java
public class SignatureViewDemo extends View {
private int color = Color.BLACK;
private Bitmap m_Bitmap;
private final Paint m_BorderPaint;
private Canvas m_Canvas;
private Point m_CropBotRight;
private Point m_CropTopLeft;
private float m_CurrentX;
private float m_CurrentY;
private final float m_DesiredDash;
private float m_LastWidth = 6.5F;
private Paint m_PenPaint;
private int m_PointIndex = 0;
private ArrayList<Point> m_Points = new ArrayList<Point>();
private final float m_StrokeWidth;
boolean m_Empty;
public SignatureViewDemo(Context paramContext) {
this(paramContext, null);
}
public SignatureViewDemo(Context paramContext,
AttributeSet paramAttributeSet) {
this(paramContext, paramAttributeSet, 0);
}
public SignatureViewDemo(Context paramContext,
AttributeSet paramAttributeSet, int paramInt) {
super(paramContext, paramAttributeSet, paramInt);
setFocusable(true);
this.m_PenPaint = new Paint();
this.m_PenPaint.setAntiAlias(true);
this.m_PenPaint.setColor(Color.BLACK);
this.m_PenPaint.setStrokeWidth(5.0F);
this.m_PenPaint.setStrokeJoin(Paint.Join.ROUND);
this.m_PenPaint.setStrokeCap(Paint.Cap.ROUND);
this.m_CurrentY = (0.0F / 0.0F);
this.m_CurrentX = (0.0F / 0.0F);
this.m_StrokeWidth = 5.0F;
this.m_DesiredDash = 10.0F;
this.m_BorderPaint = new Paint();
this.m_BorderPaint.setColor(Color.BLACK);
this.m_BorderPaint.setStyle(Paint.Style.STROKE);
this.m_BorderPaint.setStrokeWidth(this.m_StrokeWidth);
}
public void addBezier(Bezier paramBezier, float paramFloat1,
float paramFloat2) {
if (this.m_Bitmap == null) {
this.m_Bitmap = Bitmap.createBitmap(getWidth(), getHeight(),
Bitmap.Config.ARGB_8888);
this.m_Canvas = new Canvas(this.m_Bitmap);
}
paramBezier.draw(this.m_Canvas, this.m_PenPaint, paramFloat1,
paramFloat2);
}
public void addPoint(Point paramPoint) {
if ((paramPoint.getX() < this.m_CropTopLeft.getX())
&& (paramPoint.getX() >= 0.0F))
this.m_CropTopLeft.setX(paramPoint.getX());
if ((paramPoint.getY() < this.m_CropTopLeft.getY())
&& (paramPoint.getY() >= 0.0F))
this.m_CropTopLeft.setY(paramPoint.getY());
if ((paramPoint.getX() > this.m_CropBotRight.getX())
&& (paramPoint.getX() <= this.m_Canvas.getWidth()))
this.m_CropBotRight.setX(paramPoint.getX());
if ((paramPoint.getY() > this.m_CropBotRight.getY())
&& (paramPoint.getY() <= this.m_Canvas.getHeight()))
this.m_CropBotRight.setY(paramPoint.getY());
this.m_Points.add(paramPoint);
drawPoints();
}
// public void clear() {
// if (this.m_Canvas == null)
// this.m_Canvas.drawColor(0, PorterDuff.Mode.CLEAR);
// invalidate();
// // return;
// }
public void clear() {
if (this.m_Canvas == null)
return;
while (m_Empty) {
m_Canvas.drawColor(0, PorterDuff.Mode.CLEAR);
m_Empty = true;
invalidate();
return;
}
}
public void drawBitmap(Bitmap paramBitmap) {
clear();
if ((paramBitmap != null) && (this.m_Canvas != null)
&& (this.m_Canvas.getWidth() != 0)
&& (this.m_Canvas.getHeight() != 0)) {
Matrix localMatrix = new Matrix();
localMatrix.setRectToRect(
new RectF(0.0F, 0.0F, paramBitmap.getWidth(), paramBitmap
.getHeight()),
new RectF(0.0F, 0.0F, this.m_Canvas.getWidth(),
this.m_Canvas.getHeight()),
Matrix.ScaleToFit.CENTER);
this.m_Canvas.drawBitmap(paramBitmap, localMatrix, null);
m_Empty = false;
}
invalidate();
}
public void drawPoints() {
if ((m_Points.size() >= 4)
&& (4 + this.m_PointIndex <= this.m_Points.size())) {
Point localPoint1 = (Point) this.m_Points.get(this.m_PointIndex);
Point localPoint2 = (Point) this.m_Points
.get(1 + this.m_PointIndex);
Point localPoint3 = (Point) this.m_Points
.get(2 + this.m_PointIndex);
Point localPoint4 = (Point) this.m_Points
.get(3 + this.m_PointIndex);
Bezier localBezier = new Bezier(localPoint1, localPoint2,
localPoint3, localPoint4);
localBezier.setColor(Color.GREEN);
float f = strokeWidth(8.0F / localPoint4.velocityFrom(localPoint1));
addBezier(localBezier, this.m_LastWidth, f);
invalidate();
this.m_LastWidth = f;
this.m_PointIndex = (3 + this.m_PointIndex);
m_Empty = false;
}
}
public boolean isEmpty() {
return m_Empty;
}
public Bitmap getBitmap() {
return this.m_Bitmap;
}
public int getColor() {
return this.color;
}
protected void onDraw(Canvas paramCanvas) {
if (this.m_Bitmap != null)
paramCanvas.drawBitmap(this.m_Bitmap, 0.0F, 0.0F, null);
}
protected void onMeasure(int paramInt1, int paramInt2) {
int i = View.MeasureSpec.getSize(paramInt1);
int j = View.MeasureSpec.getSize(paramInt2);
this.m_CropTopLeft = new Point(i, j);
this.m_CropBotRight = new Point(0.0F, 0.0F);
setMeasuredDimension(i, j);
}
protected void onSizeChanged(int paramInt1, int paramInt2, int paramInt3,
int paramInt4) {
Bitmap localBitmap = Bitmap.createBitmap(paramInt1, paramInt2,
Bitmap.Config.ARGB_8888);
this.m_Canvas = new Canvas(localBitmap);
float f1 = 2.0F * (this.m_Canvas.getWidth() + this.m_Canvas.getHeight() - 2.0F * this.m_StrokeWidth);
float f2 = f1
* this.m_DesiredDash
/ (Math.round(f1 / (4.0F * this.m_DesiredDash)) * (4.0F * this.m_DesiredDash));
Paint localPaint = this.m_BorderPaint;
float[] arrayOfFloat = new float[2];
arrayOfFloat[0] = f2;
arrayOfFloat[1] = f2;
localPaint.setPathEffect(new DashPathEffect(arrayOfFloat, f2 / 2.0F));
clear();
if (this.m_Bitmap != null) {
Rect localRect = new Rect(0, 0, this.m_Canvas.getWidth(),
this.m_Canvas.getHeight());
this.m_Canvas.drawBitmap(this.m_Bitmap, null, localRect, null);
m_Empty = false;
}
this.m_Bitmap = localBitmap;
}
public boolean onTouchEvent(MotionEvent paramMotionEvent) {
int i = 0xFF & paramMotionEvent.getAction();
if (i == 0) {
this.m_CurrentX = paramMotionEvent.getX();
this.m_CurrentY = paramMotionEvent.getY();
addPoint(new Point(this.m_CurrentX, this.m_CurrentY,
paramMotionEvent.getEventTime()));
getParent().requestDisallowInterceptTouchEvent(true);
}
// while (m_Empty) {
if ((i == 1) || (i == 3)) {
this.m_CurrentY = (0.0F / 0.0F);
this.m_CurrentX = (0.0F / 0.0F);
this.m_Points.clear();
this.m_PointIndex = 0;
getParent().requestDisallowInterceptTouchEvent(false);
}
// if ((this.m_Points.size() < 4) || (4 + this.m_PointIndex >
// this.m_Points.size()))
// while (1 + this.m_PointIndex <= this.m_Points.size())
drawPoints();
if ((i == 2) || (i == 1)) {
for (int j = 0; j < paramMotionEvent.getHistorySize(); j++)
addPoint(new Point(paramMotionEvent.getHistoricalX(j),
paramMotionEvent.getHistoricalY(j),
paramMotionEvent.getHistoricalEventTime(j)));
addPoint(new Point(paramMotionEvent.getX(),
paramMotionEvent.getY(), paramMotionEvent.getEventTime()));
}
// }
return true;
}
public void setColor(int paramInt) {
this.color = Color.BLACK;
}
public Point getCropBotRight() {
return this.m_CropBotRight;
}
public Point getCropTopLeft() {
return this.m_CropTopLeft;
}
// public float strokeWidth(float paramFloat) {
// if (paramFloat > 11.0F)
// paramFloat = 10.0F;
// if (paramFloat < 5.0F)
// paramFloat = 6.0F;
// return paramFloat;
// }
public float strokeWidth(float paramFloat) {
if (paramFloat > 11.0F)
paramFloat = 10.0F;
while (m_Empty) {
if (paramFloat < 5.0F)
paramFloat = 6.0F;
return paramFloat;
}
return paramFloat;
}
}
Point.java
private long time;
private float x;
private float y;
public Point(float paramFloat1, float paramFloat2) {
this.x = paramFloat1;
this.y = paramFloat2;
}
public Point(float paramFloat1, float paramFloat2, long paramLong) {
this.x = paramFloat1;
this.y = paramFloat2;
this.time = paramLong;
}
protected float distanceTo(Point paramPoint) {
float f1 = this.x - paramPoint.getX();
float f2 = this.y - paramPoint.getY();
return FloatMath.sqrt(f1 * f1 + f2 * f2);
}
public long getTime() {
return this.time;
}
public float getX() {
return this.x;
}
public float getY() {
return this.y;
}
public void setX(float paramFloat) {
this.x = paramFloat;
}
public void setY(float paramFloat) {
this.y = paramFloat;
}
public float velocityFrom(Point paramPoint) {
return distanceTo(paramPoint) / (this.time - paramPoint.time);
}
}
Bezier.java
public class Bezier {
private Point controlPointOne;
private Point controlPointTwo;
private int drawSteps;
private Point endPoint;
private int mColor;
private Point startPoint;
public Bezier() {
}
public Bezier(Point paramPoint1, Point paramPoint2, Point paramPoint3,
Point paramPoint4) {
this.startPoint = paramPoint1;
this.controlPointOne = paramPoint2;
this.controlPointTwo = paramPoint3;
this.endPoint = paramPoint4;
this.drawSteps = ((int) (paramPoint1.distanceTo(paramPoint2)
+ paramPoint2.distanceTo(paramPoint3) + paramPoint3
.distanceTo(paramPoint4)));
}
public void draw(Canvas paramCanvas, Paint paramPaint, float paramFloat1,
float paramFloat2) {
float f1 = paramFloat2 - paramFloat1;
for (int i = 0; i < this.drawSteps; i++) {
float f2 = i / this.drawSteps;
float f3 = f2 * f2;
float f4 = f3 * f2;
float f5 = 1.0F - f2;
float f6 = f5 * f5;
float f7 = f6 * f5;
float f8 = f7 * this.startPoint.getX() + f2 * (3.0F * f6)
* this.controlPointOne.getX() + f3 * (3.0F * f5)
* this.controlPointTwo.getX() + f4 * this.endPoint.getX();
float f9 = f7 * this.startPoint.getY() + f2 * (3.0F * f6)
* this.controlPointOne.getY() + f3 * (3.0F * f5)
* this.controlPointTwo.getY() + f4 * this.endPoint.getY();
paramPaint.setColor(getColor());
paramPaint.setStrokeWidth(paramFloat1 + f4 * f1);
paramCanvas.drawPoint(f8, f9, paramPaint);
}
}
public int getColor() {
return this.mColor;
}
public Point getControlPointOne() {
return this.controlPointOne;
}
public Point getControlPointTwo() {
return this.controlPointTwo;
}
public int getDrawSteps() {
return this.drawSteps;
}
public Point getEndPoint() {
return this.endPoint;
}
public Point getStartPoint() {
return this.startPoint;
}
public void setColor(int paramInt) {
this.mColor = Color.BLACK;
}
public void setControlPointOne(Point paramPoint) {
this.controlPointOne = paramPoint;
}
public void setControlPointTwo(Point paramPoint) {
this.controlPointTwo = paramPoint;
}
public void setDrawSteps(int paramInt) {
this.drawSteps = paramInt;
}
public void setEndPoint(Point paramPoint) {
this.endPoint = paramPoint;
}
public void setStartPoint(Point paramPoint) {
this.startPoint = paramPoint;
}
}
推荐答案
在贝塞尔类更改抽签方法：
Change draw method in Bezier class to:
public void draw(Canvas canvas, Paint paint, float startWidth, float endWidth) {
float originalWidth = paint.getStrokeWidth();
float widthDelta = endWidth - startWidth;
for (int i = 0; i < drawSteps; i++) {
float t = ((float) i) / drawSteps;
float tt = t * t;
float ttt = tt * t;
float u = 1 - t;
float uu = u * u;
float uuu = uu * u;
float x = uuu * startPoint.x;
x += 3 * uu * t * getControlPointOne().x;
x += 3 * u * tt * getControlPointTwo().x;
x += ttt * endPoint.x;
float y = uuu * startPoint.y;
y += 3 * uu * t * getControlPointOne().y;
y += 3 * u * tt * getControlPointTwo().y;
y += ttt * endPoint.y;
paint.setStrokeWidth(startWidth + ttt * widthDelta);
canvas.drawPoint(x, y, paint);
}
paint.setStrokeWidth(originalWidth);
}
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