Android page flip

In the past two days, I have studied the paging effect of the reading software. Among them, ireader has a good effect. The effect is as follows:

 

Now let's take a look at my own results:

Draw a red line in it to determine the drawing range.

1. Mpath0.moveto (JX, JY );
2. Mpath0.quadto (HX, Hy, kx, KY );
3. Mpath0.lineto (ax, ay );
4. Mpath0.lineto (BX, );
5. Mpath0.quadto (ex, ey, CX, CY );
6. Mpath0.lineto (FX, FY );
7. Mpath0.close ();

The next step is to specify the vertices required to draw path0.

The conditions we know are: A Point Coordinate (touch point), F point coordinate (display interface size), and a straight line Eh is the vertical split line of AF.

The rest is a mathematical problem ~~

First, obtain the coordinates of the gpoint because G is the point of AF:

Apparently GX = (AX + FX)/2; Gy = (Ay + FY)/2;

Ecoordinate:

Add the subsidy line GM. The M coordinate is (GX, mheight );

According to the EGM and GMF of similar vertical triangles:

Em = GM * GM/MF;

In this way, the coordinates of the evertex are: (GX-Em, mheight)

Similarly, the coordinates of the H point can be obtained.

Coordinate C:

To simplify the calculation, we set the N point to the AG point. In this way, the triangle CJF and EHF are obtained:

Cx = ex-EF/2;

The coordinates of the cpoint are: (ex-EF/2, mheight)

Similarly, the J-point coordinate is obtained.

The following derivation requires a lot of mathematical knowledge. If you do not remember the shoes, you can consciously review them ~~

The function of a straight line is:

Y = AX + B;

Calculate the line by knowing two points: a = (y2-y1)/(x2-x1 );

B = (X2 * y1-y2 * X1)/(x2-x1 );

The coordinates of the intersection lines are: x = (b2-b1)/(a1-a2 );

Y = a1x + B1 or Y = a2x + b2

In summary, the intersection of the four points is:

X = (X4 * y3-y4 * X3)/(x4-x3)-(X2 * y1-y2 * X1)/(x2-x1 ))/

(Y2-y1)/(x2-x1)-(y4-y3)/(x4-x3 ))

= (X4 * y3-y4 * X3) (x2-x1)-(X2 * y1-y2 * X1) (x4-x3 ))/

(Y2-y1) (x4-x3)-(y4-y3) (x2-x1 ))

If the preceding four vertices A, E, C, and J are brought into the formula, B can be obtained. Similarly, K can be obtained.

D coordinate:

D is the midpoint of PE, so:

DX = (cx + bx)/2 + ex)/2

DY = (CY + by)/2 + ey)/2

Similarly, I points can be obtained.

 

OK. You can find the texture and shadow in all the points and areas to be drawn, and write the remaining values in another day.