Adopted from here
Using Bezier curve algorithm, a 3D flipping effect was created. As finger is dragged left or right, pages are turned in a beautiful view.
See a video:
The code adopted in inline Java (pager.java) :
Using Bezier curve algorithm, a 3D flipping effect was created. As finger is dragged left or right, pages are turned in a beautiful view.
See a video:
The code adopted in inline Java (pager.java) :
Java:
import android.content.Context;
import android.graphics.*;
import android.graphics.drawable.GradientDrawable;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Scroller;
public class Pager extends View {
private int mWidth = 1280;
private int mHeight = 768;
private int mCornerX = 0;
private int mCornerY = 0;
private Path mPath0;
private Path mPath1;
Bitmap mCurPageBitmap = null;
Bitmap mNextPageBitmap = null;
PointF mTouch = new PointF();
PointF mBezierStart1 = new PointF();
PointF mBezierControl1 = new PointF();
PointF mBeziervertex1 = new PointF();
PointF mBezierEnd1 = new PointF();
PointF mBezierStart2 = new PointF();
PointF mBezierControl2 = new PointF();
PointF mBeziervertex2 = new PointF();
PointF mBezierEnd2 = new PointF();
float mMiddleX;
float mMiddleY;
float mDegrees;
float mTouchToCornerDis;
ColorMatrixColorFilter mColorMatrixFilter;
Matrix mMatrix;
float[] mMatrixArray = { 0, 0, 0, 0, 0, 0, 0, 0, 1.0f };
boolean mIsRTandLB;
float mMaxLength = (float) Math.hypot(mWidth, mHeight);
int[] mBackShadowColors;
int[] mFrontShadowColors;
GradientDrawable mBackShadowDrawableLR;
GradientDrawable mBackShadowDrawableRL;
GradientDrawable mFolderShadowDrawableLR;
GradientDrawable mFolderShadowDrawableRL;
GradientDrawable mFrontShadowDrawableHBT;
GradientDrawable mFrontShadowDrawableHTB;
GradientDrawable mFrontShadowDrawableVLR;
GradientDrawable mFrontShadowDrawableVRL;
Paint mPaint;
Scroller mScroller;
public Pager(Context context, int screenWidth, int screenHeight) {
super(context);
this.mWidth = screenWidth;
this.mHeight = screenHeight;
mPath0 = new Path();
mPath1 = new Path();
createDrawable();
mPaint = new Paint();
mPaint.setStyle(Paint.Style.FILL);
ColorMatrix cm = new ColorMatrix();
float array[] = { 0.55f, 0, 0, 0, 80.0f, 0, 0.55f, 0, 0, 80.0f, 0, 0,
0.55f, 0, 80.0f, 0, 0, 0, 0.2f, 0 };
cm.set(array);
mColorMatrixFilter = new ColorMatrixColorFilter(cm);
mMatrix = new Matrix();
mScroller = new Scroller(getContext());
mTouch.x = 0.01f;
mTouch.y = 0.01f;
}
public void calcCornerXY(float x, float y) {
if (x <= mWidth / 2)
mCornerX = 0;
else
mCornerX = mWidth;
if (y <= mHeight / 2)
mCornerY = 0;
else
mCornerY = mHeight;
if ((mCornerX == 0 && mCornerY == mHeight) || (mCornerX == mWidth && mCornerY == 0))
mIsRTandLB = true;
else
mIsRTandLB = false;
}
public boolean doTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_MOVE) {
mTouch.x = event.getX();
mTouch.y = event.getY();
this.postInvalidate();
}
if (event.getAction() == MotionEvent.ACTION_DOWN) {
mTouch.x = event.getX();
mTouch.y = event.getY();
// calcCornerXY(mTouch.x, mTouch.y);
// this.postInvalidate();
}
if (event.getAction() == MotionEvent.ACTION_UP) {
if (canDragOver()) {
startAnimation(1200);
} else {
mTouch.x = mCornerX - 0.09f;
mTouch.y = mCornerY - 0.09f;
}
this.postInvalidate();
}
// return super.onTouchEvent(event);
return true;
}
public PointF getCross(PointF P1, PointF P2, PointF P3, PointF P4) {
PointF CrossP = new PointF();
float a1 = (P2.y - P1.y) / (P2.x - P1.x);
float b1 = ((P1.x * P2.y) - (P2.x * P1.y)) / (P1.x - P2.x);
float a2 = (P4.y - P3.y) / (P4.x - P3.x);
float b2 = ((P3.x * P4.y) - (P4.x * P3.y)) / (P3.x - P4.x);
CrossP.x = (b2 - b1) / (a1 - a2);
CrossP.y = a1 * CrossP.x + b1;
return CrossP;
}
private void calcPoints() {
mMiddleX = (mTouch.x + mCornerX) / 2;
mMiddleY = (mTouch.y + mCornerY) / 2;
mBezierControl1.x = mMiddleX - (mCornerY - mMiddleY) * (mCornerY - mMiddleY) / (mCornerX - mMiddleX);
mBezierControl1.y = mCornerY;
mBezierControl2.x = mCornerX;
mBezierControl2.y = mMiddleY - (mCornerX - mMiddleX) * (mCornerX - mMiddleX) / (mCornerY - mMiddleY);
mBezierStart1.x = mBezierControl1.x - (mCornerX - mBezierControl1.x) / 2;
mBezierStart1.y = mCornerY;
mBezierStart1.x < 0 mBezierStart1.x > 480
if (mTouch.x > 0 && mTouch.x < mWidth) {
if (mBezierStart1.x < 0 || mBezierStart1.x > mWidth) {
if (mBezierStart1.x < 0)
mBezierStart1.x = mWidth - mBezierStart1.x;
float f1 = Math.abs(mCornerX - mTouch.x);
float f2 = mWidth * f1 / mBezierStart1.x;
mTouch.x = Math.abs(mCornerX - f2);
float f3 = Math.abs(mCornerX - mTouch.x)
* Math.abs(mCornerY - mTouch.y) / f1;
mTouch.y = Math.abs(mCornerY - f3);
mMiddleX = (mTouch.x + mCornerX) / 2;
mMiddleY = (mTouch.y + mCornerY) / 2;
mBezierControl1.x = mMiddleX - (mCornerY - mMiddleY) * (mCornerY - mMiddleY) / (mCornerX - mMiddleX);
mBezierControl1.y = mCornerY;
mBezierControl2.x = mCornerX;
mBezierControl2.y = mMiddleY - (mCornerX - mMiddleX) * (mCornerX - mMiddleX) / (mCornerY - mMiddleY);
mBezierStart1.x = mBezierControl1.x - (mCornerX - mBezierControl1.x) / 2;
}
}
mBezierStart2.x = mCornerX;
mBezierStart2.y = mBezierControl2.y - (mCornerY - mBezierControl2.y) / 2;
mTouchToCornerDis = (float) Math.hypot((mTouch.x - mCornerX), (mTouch.y - mCornerY));
mBezierEnd1 = getCross(mTouch, mBezierControl1, mBezierStart1, mBezierStart2);
mBezierEnd2 = getCross(mTouch, mBezierControl2, mBezierStart1, mBezierStart2);
/*
* mBeziervertex1.x
* ((mBezierStart1.x+mBezierEnd1.x)/2+mBezierControl1.x)/2
* (mBezierStart1.x+ 2*mBezierControl1.x+mBezierEnd1.x) / 4
*/
mBeziervertex1.x = (mBezierStart1.x + 2 * mBezierControl1.x + mBezierEnd1.x) / 4;
mBeziervertex1.y = (2 * mBezierControl1.y + mBezierStart1.y + mBezierEnd1.y) / 4;
mBeziervertex2.x = (mBezierStart2.x + 2 * mBezierControl2.x + mBezierEnd2.x) / 4;
mBeziervertex2.y = (2 * mBezierControl2.y + mBezierStart2.y + mBezierEnd2.y) / 4;
}
private void drawCurrentPageArea(Canvas canvas, Bitmap bitmap, Path path) {
mPath0.reset();
mPath0.moveTo(mBezierStart1.x, mBezierStart1.y);
mPath0.quadTo(mBezierControl1.x, mBezierControl1.y, mBezierEnd1.x, mBezierEnd1.y);
mPath0.lineTo(mTouch.x, mTouch.y);
mPath0.lineTo(mBezierEnd2.x, mBezierEnd2.y);
mPath0.quadTo(mBezierControl2.x, mBezierControl2.y, mBezierStart2.x, mBezierStart2.y);
mPath0.lineTo(mCornerX, mCornerY);
mPath0.close();
canvas.save();
canvas.clipPath(path, Region.Op.XOR);
canvas.drawBitmap(bitmap, 0, 0, null);
canvas.restore();
}
private void drawNextPageAreaAndShadow(Canvas canvas, Bitmap bitmap) {
mPath1.reset();
mPath1.moveTo(mBezierStart1.x, mBezierStart1.y);
mPath1.lineTo(mBeziervertex1.x, mBeziervertex1.y);
mPath1.lineTo(mBeziervertex2.x, mBeziervertex2.y);
mPath1.lineTo(mBezierStart2.x, mBezierStart2.y);
mPath1.lineTo(mCornerX, mCornerY);
mPath1.close();
mDegrees = (float) Math.toDegrees(Math.atan2(mBezierControl1.x - mCornerX, mBezierControl2.y - mCornerY));
int leftx;
int rightx;
GradientDrawable mBackShadowDrawable;
if (mIsRTandLB) {
leftx = (int) (mBezierStart1.x);
rightx = (int) (mBezierStart1.x + mTouchToCornerDis / 4);
mBackShadowDrawable = mBackShadowDrawableLR;
} else {
leftx = (int) (mBezierStart1.x - mTouchToCornerDis / 4);
rightx = (int) mBezierStart1.x;
mBackShadowDrawable = mBackShadowDrawableRL;
}
canvas.save();
canvas.clipPath(mPath0);
canvas.clipPath(mPath1, Region.Op.INTERSECT);
canvas.drawBitmap(bitmap, 0, 0, null);
canvas.rotate(mDegrees, mBezierStart1.x, mBezierStart1.y);
mBackShadowDrawable.setBounds(leftx, (int) mBezierStart1.y, rightx, (int) (mMaxLength + mBezierStart1.y));
mBackShadowDrawable.draw(canvas);
canvas.restore();
}
public void setBitmaps(Bitmap bm1, Bitmap bm2) {
mCurPageBitmap = bm1;
mNextPageBitmap = bm2;
}
public void setScreen(int w, int h) {
mWidth = w;
mHeight = h;
}
@Override
protected void onDraw(Canvas canvas) {
canvas.drawColor(0xFFAAAAAA);
calcPoints();
drawCurrentPageArea(canvas, mCurPageBitmap, mPath0);
drawNextPageAreaAndShadow(canvas, mNextPageBitmap);
drawCurrentPageShadow(canvas);
drawCurrentBackArea(canvas, mCurPageBitmap);
}
private void createDrawable() {
int[] color = { 0x333333, 0xb0333333 };
mFolderShadowDrawableRL = new GradientDrawable(GradientDrawable.Orientation.RIGHT_LEFT, color);
mFolderShadowDrawableRL.setGradientType(GradientDrawable.LINEAR_GRADIENT);
mFolderShadowDrawableLR = new GradientDrawable(GradientDrawable.Orientation.LEFT_RIGHT, color);
mFolderShadowDrawableLR.setGradientType(GradientDrawable.LINEAR_GRADIENT);
mBackShadowColors = new int[] { 0xff111111, 0x111111 };
mBackShadowDrawableRL = new GradientDrawable(GradientDrawable.Orientation.RIGHT_LEFT, mBackShadowColors);
mBackShadowDrawableRL.setGradientType(GradientDrawable.LINEAR_GRADIENT);
mBackShadowDrawableLR = new GradientDrawable(GradientDrawable.Orientation.LEFT_RIGHT, mBackShadowColors);
mBackShadowDrawableLR.setGradientType(GradientDrawable.LINEAR_GRADIENT);
mFrontShadowColors = new int[] { 0x80111111, 0x111111 };
mFrontShadowDrawableVLR = new GradientDrawable(GradientDrawable.Orientation.LEFT_RIGHT, mFrontShadowColors);
mFrontShadowDrawableVLR.setGradientType(GradientDrawable.LINEAR_GRADIENT);
mFrontShadowDrawableVRL = new GradientDrawable(GradientDrawable.Orientation.RIGHT_LEFT, mFrontShadowColors);
mFrontShadowDrawableVRL.setGradientType(GradientDrawable.LINEAR_GRADIENT);
mFrontShadowDrawableHTB = new GradientDrawable(GradientDrawable.Orientation.TOP_BOTTOM, mFrontShadowColors);
mFrontShadowDrawableHTB.setGradientType(GradientDrawable.LINEAR_GRADIENT);
mFrontShadowDrawableHBT = new GradientDrawable(GradientDrawable.Orientation.BOTTOM_TOP, mFrontShadowColors);
mFrontShadowDrawableHBT.setGradientType(GradientDrawable.LINEAR_GRADIENT);
}
public void drawCurrentPageShadow(Canvas canvas) {
double degree;
if (mIsRTandLB) {
degree = Math.PI / 4 - Math.atan2(mBezierControl1.y - mTouch.y, mTouch.x - mBezierControl1.x);
} else {
degree = Math.PI / 4 - Math.atan2(mTouch.y - mBezierControl1.y, mTouch.x - mBezierControl1.x);
}
double d1 = (float) 25 * 1.414 * Math.cos(degree);
double d2 = (float) 25 * 1.414 * Math.sin(degree);
float x = (float) (mTouch.x + d1);
float y;
if (mIsRTandLB) {
y = (float) (mTouch.y + d2);
} else {
y = (float) (mTouch.y - d2);
}
mPath1.reset();
mPath1.moveTo(x, y);
mPath1.lineTo(mTouch.x, mTouch.y);
mPath1.lineTo(mBezierControl1.x, mBezierControl1.y);
mPath1.lineTo(mBezierStart1.x, mBezierStart1.y);
mPath1.close();
float rotateDegrees;
canvas.save();
canvas.clipPath(mPath0, Region.Op.XOR);
canvas.clipPath(mPath1, Region.Op.INTERSECT);
int leftx;
int rightx;
GradientDrawable mCurrentPageShadow;
if (mIsRTandLB) {
leftx = (int) (mBezierControl1.x);
rightx = (int) mBezierControl1.x + 25;
mCurrentPageShadow = mFrontShadowDrawableVLR;
} else {
leftx = (int) (mBezierControl1.x - 25);
rightx = (int) mBezierControl1.x + 1;
mCurrentPageShadow = mFrontShadowDrawableVRL;
}
rotateDegrees = (float) Math.toDegrees(Math.atan2(mTouch.x - mBezierControl1.x, mBezierControl1.y - mTouch.y));
canvas.rotate(rotateDegrees, mBezierControl1.x, mBezierControl1.y);
mCurrentPageShadow.setBounds(leftx, (int) (mBezierControl1.y - mMaxLength), rightx, (int) (mBezierControl1.y));
mCurrentPageShadow.draw(canvas);
canvas.restore();
mPath1.reset();
mPath1.moveTo(x, y);
mPath1.lineTo(mTouch.x, mTouch.y);
mPath1.lineTo(mBezierControl2.x, mBezierControl2.y);
mPath1.lineTo(mBezierStart2.x, mBezierStart2.y);
mPath1.close();
canvas.save();
canvas.clipPath(mPath0, Region.Op.XOR);
canvas.clipPath(mPath1, Region.Op.INTERSECT);
if (mIsRTandLB) {
leftx = (int) (mBezierControl2.y);
rightx = (int) (mBezierControl2.y + 25);
mCurrentPageShadow = mFrontShadowDrawableHTB;
} else {
leftx = (int) (mBezierControl2.y - 25);
rightx = (int) (mBezierControl2.y + 1);
mCurrentPageShadow = mFrontShadowDrawableHBT;
}
rotateDegrees = (float) Math.toDegrees(Math.atan2(mBezierControl2.y - mTouch.y, mBezierControl2.x - mTouch.x));
canvas.rotate(rotateDegrees, mBezierControl2.x, mBezierControl2.y);
float temp;
if (mBezierControl2.y < 0)
temp = mBezierControl2.y - mHeight;
else
temp = mBezierControl2.y;
int hmg = (int) Math.hypot(mBezierControl2.x, temp);
if (hmg > mMaxLength)
mCurrentPageShadow.setBounds((int) (mBezierControl2.x - 25) - hmg, leftx, (int) (mBezierControl2.x + mMaxLength) - hmg, rightx);
else
mCurrentPageShadow.setBounds((int) (mBezierControl2.x - mMaxLength), leftx, (int) (mBezierControl2.x), rightx);
mCurrentPageShadow.draw(canvas);
canvas.restore();
}
private void drawCurrentBackArea(Canvas canvas, Bitmap bitmap) {
int i = (int) (mBezierStart1.x + mBezierControl1.x) / 2;
float f1 = Math.abs(i - mBezierControl1.x);
int i1 = (int) (mBezierStart2.y + mBezierControl2.y) / 2;
float f2 = Math.abs(i1 - mBezierControl2.y);
float f3 = Math.min(f1, f2);
mPath1.reset();
mPath1.moveTo(mBeziervertex2.x, mBeziervertex2.y);
mPath1.lineTo(mBeziervertex1.x, mBeziervertex1.y);
mPath1.lineTo(mBezierEnd1.x, mBezierEnd1.y);
mPath1.lineTo(mTouch.x, mTouch.y);
mPath1.lineTo(mBezierEnd2.x, mBezierEnd2.y);
mPath1.close();
GradientDrawable mFolderShadowDrawable;
int left;
int right;
if (mIsRTandLB) {
left = (int) (mBezierStart1.x - 1);
right = (int) (mBezierStart1.x + f3 + 1);
mFolderShadowDrawable = mFolderShadowDrawableLR;
} else {
left = (int) (mBezierStart1.x - f3 - 1);
right = (int) (mBezierStart1.x + 1);
mFolderShadowDrawable = mFolderShadowDrawableRL;
}
canvas.save();
canvas.clipPath(mPath0);
canvas.clipPath(mPath1, Region.Op.INTERSECT);
mPaint.setColorFilter(mColorMatrixFilter);
float dis = (float) Math.hypot(mCornerX - mBezierControl1.x, mBezierControl2.y - mCornerY);
float f8 = (mCornerX - mBezierControl1.x) / dis;
float f9 = (mBezierControl2.y - mCornerY) / dis;
mMatrixArray[0] = 1 - 2 * f9 * f9;
mMatrixArray[1] = 2 * f8 * f9;
mMatrixArray[3] = mMatrixArray[1];
mMatrixArray[4] = 1 - 2 * f8 * f8;
mMatrix.reset();
mMatrix.setValues(mMatrixArray);
mMatrix.preTranslate(-mBezierControl1.x, -mBezierControl1.y);
mMatrix.postTranslate(mBezierControl1.x, mBezierControl1.y);
canvas.drawBitmap(bitmap, mMatrix, mPaint);
//canvas.drawBitmap(bitmap, mMatrix, null);
mPaint.setColorFilter(null);
canvas.rotate(mDegrees, mBezierStart1.x, mBezierStart1.y);
mFolderShadowDrawable.setBounds(left, (int) mBezierStart1.y, right, (int) (mBezierStart1.y + mMaxLength));
mFolderShadowDrawable.draw(canvas);
canvas.restore();
}
public void computeScroll() {
super.computeScroll();
if (mScroller.computeScrollOffset()) {
float x = mScroller.getCurrX();
float y = mScroller.getCurrY();
mTouch.x = x;
mTouch.y = y;
postInvalidate();
}
}
private void startAnimation(int delayMillis) {
int dx, dy;
if (mCornerX > 0) {
dx = -(int) (mWidth + mTouch.x);
} else {
dx = (int) (mWidth - mTouch.x + mWidth);
}
if (mCornerY > 0) {
dy = (int) (mHeight - mTouch.y);
} else {
dy = (int) (1 - mTouch.y); mTouch.y
}
mScroller.startScroll((int) mTouch.x, (int) mTouch.y, dx, dy, delayMillis);
}
public void abortAnimation() {
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}
}
public boolean canDragOver() {
if (mTouchToCornerDis > mWidth / 10)
return true;
return false;
}
public boolean DragToRight() {
if (mCornerX > 0)
return false;
return true;
}
}
Last edited: