### Author Topic: RotoZoom3 (Modification) by bplus  (Read 1178 times)

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• Posts: 17 ##### RotoZoom3 (Modification) by bplus
« on: September 25, 2021, 06:20:27 AM »
Author and contributor: @bplus @Galleon
Source: QB64.org Wiki and Forum
URL: https://www.qb64.org/wiki/MAPTRIANGLE
https://www.qb64.org/forum/index.php?topic=1511.msg115148#msg115148
Version: 2020 version #3
Tags: [graphics] [image]
Description:
A modification of Galleon's RotoZoom in Wiki that both scales and rotates an image, this version scales the x-axis and y-axis independently allowing some rotations of image just by changing X or Y Scales making this already powerful routine even more a versatile image tool.

Source Code (and demos with Spike Image (attached)):
Code: QB64: [Select]
1. _TITLE "Another RotoZoom Demo" 'b+ started 2020-03-02
2.
3. CONST xmax = 1200, ymax = 700, xc = 600, yc = 350
4. SCREEN _NEWIMAGE(xmax, ymax, 32)
5. _SCREENMOVE 100, 40
6. DIM SHARED s&, ao
7. DIM a, x, y, x1, y1, xs, dxs, ddxs, ys, dys, ddys, maxScale
8.
9. ' Starting from an image I pulled from Internet, I used Paint 3D to give it a transparent background.
10. s& = _LOADIMAGE("tspike.png") 't for transparent background
11.
12.
13. ' Standard Rotation about the image center on a given X, Y location. Rotating image in middle of screen,
14. ' I used something like this to find ideal angle for level point on left head on right.
15. WHILE _KEYDOWN(27) = 0
16.     a = a + _PI(1 / 36)
17.     IF a > _PI(1.999) THEN a = 0
18.     RotoZoom3 xc, yc, s&, 1, 1, a
19.     PRINT "Raw image rotation:": PRINT
20.     PRINT "radian angle:"; a; "   degrees:"; _R2D(a) \ 1; " press key for next angle... esc to rotate on y axis"
21.     WHILE LEN(INKEY\$) = 0: _LIMIT 60: WEND
22.
23. ao = _PI(.27) ' I have to offset the image angle by this amount so that the spike point is on the left
24. '               and the head is on the right at 0 degrees or radians.
25.
26.
27. 'Demo of the independent x and y scale for axis rotations
28. maxScale = 4: dxs = .01: ddxs = 1: xs = maxScale:
29.     PRINT "Press any for rotation on x axis..."
30.     RotoZoom3 xc, yc, s&, xs, maxScale, ao
31.     IF xs + dxs > maxScale OR xs + dxs < -maxScale THEN ddxs = ddxs * -1
32.     xs = xs + dxs * ddxs
33.     _LIMIT 60
34.
35. ys = maxScale: dys = .01: ddys = 1
36.     PRINT "Press any to see layout of image over whole screen and end demo..."
37.     RotoZoom3 xc, yc, s&, maxScale, ys, ao
38.     IF ys + dys > maxScale OR ys + dys < -maxScale THEN ddys = ddys * -1
39.     ys = ys + dys * ddys
40.     _LIMIT 60
41.
42. ' Demo of an applied layout on screen
43. COLOR , &HFFBBBBBB: CLS ' the image has slight gray halo so hide with gray background
44. FOR x = 40 TO _WIDTH - 40 STEP 20
45.     RotoZoom3 x, 15, s&, .2, .2, _PI(1.5 + .27)
46.     RotoZoom3 x, _HEIGHT - 15, s&, .2, .2, _PI(.5 + .27)
47. FOR y = 40 TO _HEIGHT - 40 STEP 20
48.     RotoZoom3 15, y, s&, .2, .2, _PI(1 + .27)
49.     RotoZoom3 _WIDTH - 15, y, s&, .2, .2, _PI(.27)
50. FOR a = 0 TO _PI(2) STEP _PI(1 / 6)
51.     x1 = xc + 200 * COS(a)
52.     y1 = yc + 200 * SIN(a)
53.     RotoZoom3 x1, y1, s&, 2, 2, a + ao
54.
55. 'And finally a little show. What is better than a knife thrower throwing bananas?
56. WHILE _KEYDOWN(27) = 0
57.     drawKite xc, .9 * ymax, 600, a + ao
58.     _LIMIT 30
59.     a = a + _PI(2 / 360)
60.
61. SUB drawKite (x, y, s, a)
62.     RotoZoom3 x, y, s&, s / _WIDTH(s&), s / _HEIGHT(s&), a + ao
63.     IF s > 10 THEN
64.         drawKite x + .5 * s * COS(_PI(2) - a), (y - .25 * s) + .25 * s * SIN(_PI(2) - a), s / 1.5, a
65.         drawKite x + .5 * s * COS(_PI + a), (y - .25 * s) + .25 * s * SIN(_PI + a), s / 1.5, a
66.
67. ' Description:
68. ' Started from a mod of Galleon's in Wiki that both scales and rotates an image.
69. ' This version scales the x-axis and y-axis independently allowing rotations of image just by changing X or Y Scales
70. ' making this tightly coded routine a very powerful and versatile image tool.
71. SUB RotoZoom3 (X AS LONG, Y AS LONG, Image AS LONG, xScale AS SINGLE, yScale AS SINGLE, radianRotation AS SINGLE)
72.     ' This assumes you have set your drawing location with _DEST or default to screen.
73.     ' X, Y - is where you want to put the middle of the image
74.     ' Image - is the handle assigned with _LOADIMAGE
75.     ' xScale, yScale - are shrinkage < 1 or magnification > 1 on the given axis, 1 just uses image size.
76.     ' These are multipliers so .5 will create image .5 size on given axis and 2 for twice image size.
77.     ' radianRotation is the Angle in Radian units to rotate the image
78.     ' note: Radian units for rotation because it matches angle units of other Basic Trig functions
79.     '       and saves a little time converting from degree.
80.     '       Use the _D2R() function if you prefer to work in degree units for angles.
81.
82.     DIM px(3) AS SINGLE: DIM py(3) AS SINGLE ' simple arrays for x, y to hold the 4 corners of image
83.     DIM W&, H&, sinr!, cosr!, i&, x2&, y2& '   variables for image manipulation
84.     W& = _WIDTH(Image&): H& = _HEIGHT(Image&)
85.     px(0) = -W& / 2: py(0) = -H& / 2 'left top corner
86.     px(1) = -W& / 2: py(1) = H& / 2 ' left bottom corner
87.     px(2) = W& / 2: py(2) = H& / 2 '  right bottom
88.     px(3) = W& / 2: py(3) = -H& / 2 ' right top
90.     FOR i& = 0 TO 3 ' calc new point locations with rotation and zoom
91.         x2& = xScale * (px(i&) * cosr! + sinr! * py(i&)) + X: y2& = yScale * (py(i&) * cosr! - px(i&) * sinr!) + Y
92.         px(i&) = x2&: py(i&) = y2&
93.     _MAPTRIANGLE _SEAMLESS(0, 0)-(0, H& - 1)-(W& - 1, H& - 1), Image TO(px(0), py(0))-(px(1), py(1))-(px(2), py(2))
94.     _MAPTRIANGLE _SEAMLESS(0, 0)-(W& - 1, 0)-(W& - 1, H& - 1), Image TO(px(0), py(0))-(px(3), py(3))-(px(2), py(2))
95.
96.

Attachments: Another RotoZoom Demo.zip