1 // Copyright 2000-2005 the Contributors, as shown in the revision logs.
2 // Licensed under the GNU General Public License version 2 ("the License").
3 // You may not use this file except in compliance with the License.
6 package org.ibex.graphics;
9 /** an affine transform; all operations are destructive */
10 public final class Affine {
15 public float a, b, c, d, e, f;
17 Affine(float _a, float _b, float _c, float _d, float _e, float _f) { a = _a; b = _b; c = _c; d = _d; e = _e; f = _f; }
18 public String toString() { return "[ " + a + ", " + b + ", " + c + ", " + d + ", " + e + ", " + f + " ]"; }
19 public Affine copy() { return new Affine(a, b, c, d, e, f); }
20 public static Affine identity() { return new Affine(1, 0, 0, 1, 0, 0); }
21 public static Affine scale(float sx, float sy) { return new Affine(sx, 0, 0, sy, 0, 0); }
22 public static Affine shear(float degrees) {
23 return new Affine(1, 0, (float)Math.tan(degrees * (float)(Math.PI / 180.0)), 1, 0, 0); }
24 public static Affine translate(float tx, float ty) { return new Affine(1, 0, 0, 1, tx, ty); }
25 public static Affine flip(boolean horiz, boolean vert) { return new Affine(horiz ? -1 : 1, 0, 0, vert ? -1 : 1, 0, 0); }
26 public float multiply_px(float x, float y) { return x * a + y * c + e; }
27 public float multiply_py(float x, float y) { return x * b + y * d + f; }
28 public float sign(float x) { return x >= 0 ? 1 : -1; }
29 public float divide_boundingbox_x(float bx, float by, float aspect) {
30 return (float)Math.min(Math.abs(bx * (sign(a) * sign(c)) / (aspect * a + c)),
31 Math.abs(by * (sign(b) * sign(d)) / (aspect * b + d)));
33 public float multiply_boundingbox_x(float x, float y) {
34 return (float)Math.max((int)Math.abs(multiply_px(x, y) - multiply_px(0, 0)),
35 (int)Math.abs(multiply_px(x, 0) - multiply_px(0, y))); }
36 public float multiply_boundingbox_y(float x, float y) {
37 return (float)Math.max((int)Math.abs(multiply_py(x, y) - multiply_py(0, 0)),
38 (int)Math.abs(multiply_py(x, 0) - multiply_py(0, y))); }
39 public boolean equalsIgnoringTranslation(Affine x) { return a == x.a && b == x.b && c == x.c && d == x.d; }
40 public Affine clearTranslation() { e = (float)0.0; f = (float)0.0; return this; }
42 public boolean equals(Object o) {
43 if (!(o instanceof Affine)) return false;
45 return a == x.a && b == x.b && c == x.c && d == x.d && e == x.e && f == x.f;
48 public static Affine rotate(float degrees) {
49 float s = (float)Math.sin(degrees * (float)(Math.PI / 180.0));
50 float c = (float)Math.cos(degrees * (float)(Math.PI / 180.0));
51 return new Affine(c, s, -s, c, 0, 0);
54 /** this = this * a */
55 public Affine multiply(Affine A) {
56 float _a = this.a * A.a + this.b * A.c;
57 float _b = this.a * A.b + this.b * A.d;
58 float _c = this.c * A.a + this.d * A.c;
59 float _d = this.c * A.b + this.d * A.d;
60 float _e = this.e * A.a + this.f * A.c + A.e;
61 float _f = this.e * A.b + this.f * A.d + A.f;
62 a = _a; b = _b; c = _c; d = _d; e = _e; f = _f;
66 /** this = a * this */
67 public Affine premultiply(Affine A) {
68 float _a = A.a * this.a + A.b * this.c;
69 float _b = A.a * this.b + A.b * this.d;
70 float _c = A.c * this.a + A.d * this.c;
71 float _d = A.c * this.b + A.d * this.d;
72 float _e = A.e * this.a + A.f * this.c + this.e;
73 float _f = A.e * this.b + A.f * this.d + this.f;
74 a = _a; b = _b; c = _c; d = _d; e = _e; f = _f;
78 public Affine invert() {
79 float det = 1 / (a * d - b * c);
81 float _b = -1 * b * det;
82 float _c = -1 * c * det;
84 float _e = -1 * e * a - f * c;
85 float _f = -1 * e * b - f * d;
86 a = _a; b = _b; c = _c; d = _d; e = _e; f = _f;
90 public static Affine parse(String t) {
91 if (t == null) return null;
93 Affine ret = Affine.identity();
94 while (t.length() > 0) {
95 if (t.startsWith("skewX(")) {
98 } else if (t.startsWith("shear(")) {
99 // FIXME: nonstandard; remove this
100 ret.multiply(Affine.shear(Float.parseFloat(t.substring(t.indexOf('(') + 1, t.indexOf(')')))));
102 } else if (t.startsWith("skewY(")) {
105 } else if (t.startsWith("rotate(")) {
106 String sub = t.substring(t.indexOf('(') + 1, t.indexOf(')'));
107 if (sub.indexOf(',') != -1) {
108 float angle = Float.parseFloat(sub.substring(0, sub.indexOf(',')));
109 sub = sub.substring(sub.indexOf(',') + 1);
110 float cx = Float.parseFloat(sub.substring(0, sub.indexOf(',')));
111 sub = sub.substring(sub.indexOf(',') + 1);
112 float cy = Float.parseFloat(sub);
113 ret.multiply(Affine.translate(cx, cy));
114 ret.multiply(Affine.rotate(angle));
115 ret.multiply(Affine.translate(-1 * cx, -1 * cy));
117 ret.multiply(Affine.rotate(Float.parseFloat(t.substring(t.indexOf('(') + 1, t.indexOf(')')))));
120 } else if (t.startsWith("translate(")) {
121 String sub = t.substring(t.indexOf('(') + 1, t.indexOf(')'));
122 if (sub.indexOf(',') > -1) {
123 ret.multiply(Affine.translate(Float.parseFloat(t.substring(t.indexOf('(') + 1, t.indexOf(','))),
124 Float.parseFloat(t.substring(t.indexOf(',') + 1, t.indexOf(')')))));
126 ret.multiply(Affine.translate(Float.parseFloat(t.substring(t.indexOf('(') + 1, t.indexOf(','))), 0));
129 } else if (t.startsWith("flip(")) {
130 String which = t.substring(t.indexOf('(') + 1, t.indexOf(')'));
131 ret.multiply(Affine.flip(which.equals("horizontal"), which.equals("vertical")));
133 } else if (t.startsWith("scale(")) {
134 String sub = t.substring(t.indexOf('(') + 1, t.indexOf(')'));
135 if (sub.indexOf(',') > -1) {
136 ret.multiply(Affine.scale(Float.parseFloat(t.substring(t.indexOf('(') + 1, t.indexOf(','))),
137 Float.parseFloat(t.substring(t.indexOf(',') + 1, t.indexOf(')')))));
139 ret.multiply(Affine.scale(Float.parseFloat(t.substring(t.indexOf('(') + 1, t.indexOf(','))),
140 Float.parseFloat(t.substring(t.indexOf('(') + 1, t.indexOf(',')))));
143 } else if (t.startsWith("matrix(")) {
144 // FIXME: is this mapped right?
145 float d[] = new float[6];
146 StringTokenizer st = new StringTokenizer(t, ",", false);
147 for(int i=0; i<6; i++)
148 d[i] = Float.parseFloat(st.nextToken());
149 ret.multiply(new Affine(d[0], d[1], d[2], d[3], d[4], d[5]));
151 t = t.substring(t.indexOf(')') + 1).trim();