请问在TCAS中怎么旋转PIX？

乱步

沿z轴的旋转貌似可以先转成image再rotate， 如果是沿x轴和y轴呢

milkyjing

貌似我没见到直接的方法, 但如果有一定编码能力的话, 可以按照如下思路去编写:

1. def ca_frz(x, y, a):
   
2.     x2 = x * cos(a) + y * sin(a)
   
3.     y2 = x * sin(a) + y * cos(a)
   
4.     return x2, y2
   
5. 
   
6. def ca_fry(x, y, a):
   
7.     x2 = x * cos(a)
   
8.     y2 = y
   
9.     return x2, y2
   
10. 
    
11. def ca_frx(x, y, a):
    
12.     x2 = x
    
13.     y2 = y * cos(a)
    
14.     return x2, y2

复制代码

这个是我为cairo模块写的旋转代码, 利用这个原理, 以及双线性插值

1. int x = floor(u);
   
2.    int y = floor(v);
   
3.    double u_ratio = u - x;
   
4.    double v_ratio = v - y;
   
5.    double u_opposite = 1 - u_ratio;
   
6.    double v_opposite = 1 - v_ratio;
   
7.    double result = (tex[x][y]   * u_opposite  + tex[x+1][y]   * u_ratio) * v_opposite +
   
8.                    (tex[x][y+1] * u_opposite  + tex[x+1][y+1] * u_ratio) * v_ratio;

复制代码

(目标PIX中的一点由源PIX中最近的4点决定)

关于PIX的操作, 可以看最新版的TCAX中的tcaxPy.py, 里面有一些相关的函数可供参考.

p.s. 我没时间来编码这东西了, 所以靠自己努力吧, Fight~

milkyjing

抽空写了个简单的, 基于最近点的绕X轴旋转代码. 未测试

1. # PIX rotate around x-axis, nearest point approach,
   
2. # the position of PIX is maintained by fixing the middle of the original PIX still
   
3. # point (x, y) maps to a new point (u, v) by the formula u = x, v = y * cos(ag)
   
4. # so destination resolution of PIX is dst_width = src_width, dst_height = src_height * cos(ag)
   
5. def PixRotateX_nearest(PIX, ag):
   
6.     src_width = PIX[1][0]
   
7.     src_height = PIX[1][1]
   
8.     dst_width = src_width
   
9.     dst_height = int(src_height * cos(ag) + 0.5)
   
10.     PIX_pos = (PIX[0][0], PIX[0][1] + (src_height - dst_height) / 2)
    
11.     PIX_res = (dst_width, dst_height)
    
12.     size = dst_height * dst_width * 4
    
13.     PIX_rgba = [0 for c in range(size)]
    
14.     for h in range(dst_height):
    
15.         for w in range(dst_width):
    
16.             dst_idx = 4 * (h * dst_width + w)
    
17.             src_idx = 4 * (int(h * cos(ag) + 0.5) * src_width + w)
    
18.             PIX_rgba[dst_idx] = PIX[2][src_idx]
    
19.             PIX_rgba[dst_idx + 1] = PIX[2][src_idx + 1]
    
20.             PIX_rgba[dst_idx + 2] = PIX[2][src_idx + 2]
    
21.             PIX_rgba[dst_idx + 3] = PIX[2][src_idx + 3]
    
22.     return (PIX_pos, PIX_res, tuple(PIX_rgba))

复制代码

milkyjing

经测试, 上帖第17行代码 h * cos(ag) 应改为 h / cos(ag), 顺带写了绕Y轴的最近点算法版本.
注: 不管是绕X轴旋转抑或是绕Y轴旋转, 都未考虑进"透视感"(即, 近端变大, 远端变小). 有待升级

1. from math import cos
   
2. 
   
3. # PIX rotate around x-axis, nearest point approach,
   
4. # the position of PIX is maintained by fixing the middle of the original PIX still
   
5. # point (x, y) maps to a new point (u, v) by the formula u = x, v = y * cos(ag)
   
6. # so destination resolution of PIX is dst_width = src_width, dst_height = src_height * cos(ag)
   
7. def PixRotateX_nearest(PIX, ag):
   
8.     src_width = PIX[1][0]
   
9.     src_height = PIX[1][1]
   
10.     dst_width = src_width
    
11.     dst_height = int(src_height * cos(ag) + 0.5)
    
12.     PIX_pos = (PIX[0][0], PIX[0][1] + (src_height - dst_height) / 2)
    
13.     PIX_res = (dst_width, dst_height)
    
14.     size = dst_height * dst_width * 4
    
15.     PIX_rgba = [0 for c in range(size)]
    
16.     for h in range(dst_height):
    
17.         for w in range(dst_width):
    
18.             dst_idx = 4 * (h * dst_width + w)
    
19.             src_idx = 4 * (int(h / cos(ag) + 0.5) * src_width + w)
    
20.             PIX_rgba[dst_idx] = PIX[2][src_idx]
    
21.             PIX_rgba[dst_idx + 1] = PIX[2][src_idx + 1]
    
22.             PIX_rgba[dst_idx + 2] = PIX[2][src_idx + 2]
    
23.             PIX_rgba[dst_idx + 3] = PIX[2][src_idx + 3]
    
24.     return (PIX_pos, PIX_res, tuple(PIX_rgba))
    
25. 
    
26. # PIX rotate around y-axis, nearest point approach,
    
27. # the position of PIX is maintained by fixing the middle of the original PIX still
    
28. # point (x, y) maps to a new point (u, v) by the formula u = x * cos(ag), v = y
    
29. # so destination resolution of PIX is dst_width = src_width * cos(ag), dst_height = src_height
    
30. def PixRotateY_nearest(PIX, ag):
    
31.     src_width = PIX[1][0]
    
32.     src_height = PIX[1][1]
    
33.     dst_width = int(src_width * cos(ag) + 0.5)
    
34.     dst_height = src_height
    
35.     PIX_pos = (PIX[0][0] + (src_width - dst_width) / 2, PIX[0][1])
    
36.     PIX_res = (dst_width, dst_height)
    
37.     size = dst_height * dst_width * 4
    
38.     PIX_rgba = [0 for c in range(size)]
    
39.     for h in range(dst_height):
    
40.         for w in range(dst_width):
    
41.             dst_idx = 4 * (h * dst_width + w)
    
42.             src_idx = 4 * (h * src_width + int(w / cos(ag) + 0.5))
    
43.             PIX_rgba[dst_idx] = PIX[2][src_idx]
    
44.             PIX_rgba[dst_idx + 1] = PIX[2][src_idx + 1]
    
45.             PIX_rgba[dst_idx + 2] = PIX[2][src_idx + 2]
    
46.             PIX_rgba[dst_idx + 3] = PIX[2][src_idx + 3]
    
47.     return (PIX_pos, PIX_res, tuple(PIX_rgba))

复制代码

milkyjing

VSFilter中, 关于frx, fry, frz的代码是(同时输入3个角度以及一个坐标原点, 一同进行变换, 未指定的角度, 默认为0)

1. void CWord::Transform(CPoint org)
   
2. {
   
3.         double scalex = m_style.fontScaleX/100;
   
4.         double scaley = m_style.fontScaleY/100;
   
5. 
   
6.         double caz = cos((3.1415/180)*m_style.fontAngleZ);
   
7.         double saz = sin((3.1415/180)*m_style.fontAngleZ);
   
8.         double cax = cos((3.1415/180)*m_style.fontAngleX);
   
9.         double sax = sin((3.1415/180)*m_style.fontAngleX);
   
10.         double cay = cos((3.1415/180)*m_style.fontAngleY);
    
11.         double say = sin((3.1415/180)*m_style.fontAngleY);
    
12. 
    
13.         for(int i = 0; i < mPathPoints; i++)
    
14.         {
    
15.                 double x, y, z, xx, yy, zz;
    
16. 
    
17.                 x = scalex * (mpPathPoints[i].x + m_style.fontShiftX * mpPathPoints[i].y) - org.x;
    
18.                 y = scaley * (mpPathPoints[i].y + m_style.fontShiftY * mpPathPoints[i].x) - org.y;
    
19.                 z = 0;
    
20. 
    
21.                 xx = x*caz + y*saz;
    
22.                 yy = -(x*saz - y*caz);
    
23.                 zz = z;
    
24. 
    
25.                 x = xx;
    
26.                 y = yy*cax + zz*sax;
    
27.                 z = yy*sax - zz*cax;
    
28. 
    
29.                 xx = x*cay + z*say;
    
30.                 yy = y;
    
31.                 zz = x*say - z*cay;
    
32. 
    
33.                 zz = max(zz, -19000);
    
34. 
    
35.                 x = (xx * 20000) / (zz + 20000);
    
36.                 y = (yy * 20000) / (zz + 20000);
    
37. 
    
38.                 mpPathPoints[i].x = (LONG)(x + org.x + 0.5);
    
39.                 mpPathPoints[i].y = (LONG)(y + org.y + 0.5);
    
40.         }
    
41. }

复制代码

six

别折磨好少年了，牛奶大，直接搞内置函数得了@@

乱步

受益良多！感谢牛奶大