dlib.image.transform source code

1 /*
2 Copyright (c) 2016-2021 Timur Gafarov
3 
4 Boost Software License - Version 1.0 - August 17th, 2003
5 
6 Permission is hereby granted, free of charge, to any person or organization
7 obtaining a copy of the software and accompanying documentation covered by
8 this license (the "Software") to use, reproduce, display, distribute,
9 execute, and transmit the Software, and to prepare derivative works of the
10 Software, and to permit third-parties to whom the Software is furnished to
11 do so, all subject to the following:
12 
13 The copyright notices in the Software and this entire statement, including
14 the above license grant, this restriction and the following disclaimer,
15 must be included in all copies of the Software, in whole or in part, and
16 all derivative works of the Software, unless such copies or derivative
17 works are solely in the form of machine-executable object code generated by
18 a source language processor.
19 
20 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
21 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
22 FITNESS FOR A PARTICULAR PURPOSE, TITLE AND NON-INFRINGEMENT. IN NO EVENT
23 SHALL THE COPYRIGHT HOLDERS OR ANYONE DISTRIBUTING THE SOFTWARE BE LIABLE
24 FOR ANY DAMAGES OR OTHER LIABILITY, WHETHER IN CONTRACT, TORT OR OTHERWISE,
25 ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
26 DEALINGS IN THE SOFTWARE.
27 */
28 
29 /**
30  * Geometric ransformations of images
31  *
32  * Copyright: Timur Gafarov 2016-2021.
33  * License: $(LINK2 boost.org/LICENSE_1_0.txt, Boost License 1.0).
34  * Authors: Timur Gafarov
35  */
36 module dlib.image.transform;
37 
38 import dlib.math.vector;
39 import dlib.math.matrix;
40 import dlib.math.transformation;
41 import dlib.math.utils;
42 
43 import dlib.image.image;
44 import dlib.image.color;
45 
46 /// Tranforms an image with affine 3x3 matrix
47 SuperImage affineTransformImage(SuperImage img, SuperImage outp, Matrix3x3f m)
48 {
49     SuperImage res;
50     if (outp)
51         res = outp;
52     else
53         res = img.createSameFormat(img.width, img.height);
54 
55     foreach(y; 0..res.height)
56     foreach(x; 0..res.width)
57     {
58         Vector2f v1 = Vector2f(x, y).affineTransform2D(m);
59         res[x, y] = bilinearPixel(img, v1.x, v1.y);
60     }
61 
62     return res;
63 }
64 
65 /// ditto
66 SuperImage affineTransformImage(SuperImage img, Matrix3x3f m)
67 {
68     return affineTransformImage(img, null, m);
69 }
70 
71 /// Translates an image (positive x goes right, positive y goes down)
72 SuperImage translateImage(SuperImage img, SuperImage outp, Vector2f t)
73 {
74     Matrix3x3f m = translationMatrix2D(-t);
75     return affineTransformImage(img, outp, m);
76 }
77 
78 /// ditto
79 SuperImage translateImage(SuperImage img, Vector2f t)
80 {
81     return translateImage(img, null, t);
82 }
83 
84 /// Rotates an image clockwise around its center. Angle is in degrees.
85 SuperImage rotateImage(SuperImage img, SuperImage outp, float angle)
86 {
87     Vector2f center = Vector2f(img.width, img.height) * 0.5f;
88     Matrix3x3f m =
89       translationMatrix2D(center) *
90       rotationMatrix2D(degtorad(angle)) *
91       translationMatrix2D(-center);
92     return affineTransformImage(img, outp, m);
93 }
94 
95 /// ditto
96 SuperImage rotateImage(SuperImage img, float angle)
97 {
98     return rotateImage(img, null, angle);
99 }
100 
101 /// Scales an image
102 SuperImage scaleImage(SuperImage img, SuperImage outp, Vector2f s)
103 {
104     Matrix3x3f m = scaleMatrix2D(Vector2f(1, 1) / s);
105     return affineTransformImage(img, outp, m);
106 }
107 
108 /// ditto
109 SuperImage scaleImage(SuperImage img, Vector2f s)
110 {
111     return scaleImage(img, null, s);
112 }
113 
114 /// Uniformly scales an image
115 SuperImage scaleImage(SuperImage img, SuperImage outp, float s)
116 {
117     float sinv = 1.0f / s;
118     Matrix3x3f m = scaleMatrix2D(Vector2f(sinv, sinv));
119     return affineTransformImage(img, outp, m);
120 }
121 
122 /// ditto
123 SuperImage scaleImage(SuperImage img, float s)
124 {
125     return scaleImage(img, null, s);
126 }