Transform.cpp revision 4c05dd175ee3bd5119eecf368742b6510a8cfa6c 
1/*
2 * Copyright (C) 2007 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <math.h>
18
19#include <cutils/compiler.h>
20#include <utils/String8.h>
21#include <ui/Region.h>
22
23#include "clz.h"
24#include "Transform.h"
25
26// ---------------------------------------------------------------------------
27
28namespace android {
29
30// ---------------------------------------------------------------------------
31
32Transform::Transform() {
33    reset();
34}
35
36Transform::Transform(const Transform&  other)
37    : mMatrix(other.mMatrix), mType(other.mType) {
38}
39
40Transform::Transform(uint32_t orientation) {
41    set(orientation, 0, 0);
42}
43
44Transform::~Transform() {
45}
46
47static const float EPSILON = 0.0f;
48
49bool Transform::isZero(float f) {
50    return fabs(f) <= EPSILON;
51}
52
53bool Transform::absIsOne(float f) {
54    return isZero(fabs(f) - 1.0f);
55}
56
57Transform Transform::operator * (const Transform& rhs) const
58{
59    if (CC_LIKELY(mType == IDENTITY))
60        return rhs;
61
62    Transform r(*this);
63    if (rhs.mType == IDENTITY)
64        return r;
65
66    // TODO: we could use mType to optimize the matrix multiply
67    const mat33& A(mMatrix);
68    const mat33& B(rhs.mMatrix);
69          mat33& D(r.mMatrix);
70    for (int i=0 ; i<3 ; i++) {
71        const float v0 = A[0][i];
72        const float v1 = A[1][i];
73        const float v2 = A[2][i];
74        D[0][i] = v0*B[0][0] + v1*B[0][1] + v2*B[0][2];
75        D[1][i] = v0*B[1][0] + v1*B[1][1] + v2*B[1][2];
76        D[2][i] = v0*B[2][0] + v1*B[2][1] + v2*B[2][2];
77    }
78    r.mType |= rhs.mType;
79
80    // TODO: we could recompute this value from r and rhs
81    r.mType &= 0xFF;
82    r.mType |= UNKNOWN_TYPE;
83    return r;
84}
85
86float const* Transform::operator [] (int i) const {
87    return mMatrix[i].v;
88}
89
90bool Transform::transformed() const {
91    return type() > TRANSLATE;
92}
93
94float Transform::tx() const {
95    return mMatrix[2][0];
96}
97
98float Transform::ty() const {
99    return mMatrix[2][1];
100}
101
102void Transform::reset() {
103    mType = IDENTITY;
104    for(int i=0 ; i<3 ; i++) {
105        vec3& v(mMatrix[i]);
106        for (int j=0 ; j<3 ; j++)
107            v[j] = ((i==j) ? 1.0f : 0.0f);
108    }
109}
110
111void Transform::set(float tx, float ty)
112{
113    mMatrix[2][0] = tx;
114    mMatrix[2][1] = ty;
115    mMatrix[2][2] = 1.0f;
116
117    if (isZero(tx) && isZero(ty)) {
118        mType &= ~TRANSLATE;
119    } else {
120        mType |= TRANSLATE;
121    }
122}
123
124void Transform::set(float a, float b, float c, float d)
125{
126    mat33& M(mMatrix);
127    M[0][0] = a;    M[1][0] = b;
128    M[0][1] = c;    M[1][1] = d;
129    M[0][2] = 0;    M[1][2] = 0;
130    mType = UNKNOWN_TYPE;
131}
132
133status_t Transform::set(uint32_t flags, float w, float h)
134{
135    if (flags & ROT_INVALID) {
136        // that's not allowed!
137        reset();
138        return BAD_VALUE;
139    }
140
141    Transform H, V, R;
142    if (flags & ROT_90) {
143        // w & h are inverted when rotating by 90 degrees
144        swap(w, h);
145    }
146
147    if (flags & FLIP_H) {
148        H.mType = (FLIP_H << 8) | SCALE;
149        H.mType |= isZero(w) ? IDENTITY : TRANSLATE;
150        mat33& M(H.mMatrix);
151        M[0][0] = -1;
152        M[2][0] = w;
153    }
154
155    if (flags & FLIP_V) {
156        V.mType = (FLIP_V << 8) | SCALE;
157        V.mType |= isZero(h) ? IDENTITY : TRANSLATE;
158        mat33& M(V.mMatrix);
159        M[1][1] = -1;
160        M[2][1] = h;
161    }
162
163    if (flags & ROT_90) {
164        const float original_w = h;
165        R.mType = (ROT_90 << 8) | ROTATE;
166        R.mType |= isZero(original_w) ? IDENTITY : TRANSLATE;
167        mat33& M(R.mMatrix);
168        M[0][0] = 0;    M[1][0] =-1;    M[2][0] = original_w;
169        M[0][1] = 1;    M[1][1] = 0;
170    }
171
172    *this = (R*(H*V));
173    return NO_ERROR;
174}
175
176Transform::vec2 Transform::transform(const vec2& v) const {
177    vec2 r;
178    const mat33& M(mMatrix);
179    r[0] = M[0][0]*v[0] + M[1][0]*v[1] + M[2][0];
180    r[1] = M[0][1]*v[0] + M[1][1]*v[1] + M[2][1];
181    return r;
182}
183
184Transform::vec3 Transform::transform(const vec3& v) const {
185    vec3 r;
186    const mat33& M(mMatrix);
187    r[0] = M[0][0]*v[0] + M[1][0]*v[1] + M[2][0]*v[2];
188    r[1] = M[0][1]*v[0] + M[1][1]*v[1] + M[2][1]*v[2];
189    r[2] = M[0][2]*v[0] + M[1][2]*v[1] + M[2][2]*v[2];
190    return r;
191}
192
193void Transform::transform(float* point, int x, int y) const
194{
195    vec2 v(x, y);
196    v = transform(v);
197    point[0] = v[0];
198    point[1] = v[1];
199}
200
201Rect Transform::makeBounds(int w, int h) const
202{
203    return transform( Rect(w, h) );
204}
205
206Rect Transform::transform(const Rect& bounds) const
207{
208    Rect r;
209    vec2 lt( bounds.left,  bounds.top    );
210    vec2 rt( bounds.right, bounds.top    );
211    vec2 lb( bounds.left,  bounds.bottom );
212    vec2 rb( bounds.right, bounds.bottom );
213
214    lt = transform(lt);
215    rt = transform(rt);
216    lb = transform(lb);
217    rb = transform(rb);
218
219    r.left   = floorf(min(lt[0], rt[0], lb[0], rb[0]) + 0.5f);
220    r.top    = floorf(min(lt[1], rt[1], lb[1], rb[1]) + 0.5f);
221    r.right  = floorf(max(lt[0], rt[0], lb[0], rb[0]) + 0.5f);
222    r.bottom = floorf(max(lt[1], rt[1], lb[1], rb[1]) + 0.5f);
223
224    return r;
225}
226
227Region Transform::transform(const Region& reg) const
228{
229    Region out;
230    if (CC_UNLIKELY(transformed())) {
231        if (CC_LIKELY(preserveRects())) {
232            Region::const_iterator it = reg.begin();
233            Region::const_iterator const end = reg.end();
234            while (it != end) {
235                out.orSelf(transform(*it++));
236            }
237        } else {
238            out.set(transform(reg.bounds()));
239        }
240    } else {
241        int xpos = floorf(tx() + 0.5f);
242        int ypos = floorf(ty() + 0.5f);
243        out = reg.translate(xpos, ypos);
244    }
245    return out;
246}
247
248uint32_t Transform::type() const
249{
250    if (mType & UNKNOWN_TYPE) {
251        // recompute what this transform is
252
253        const mat33& M(mMatrix);
254        const float a = M[0][0];
255        const float b = M[1][0];
256        const float c = M[0][1];
257        const float d = M[1][1];
258        const float x = M[2][0];
259        const float y = M[2][1];
260
261        bool scale = false;
262        uint32_t flags = ROT_0;
263        if (isZero(b) && isZero(c)) {
264            if (a<0)    flags |= FLIP_H;
265            if (d<0)    flags |= FLIP_V;
266            if (!absIsOne(a) || !absIsOne(d)) {
267                scale = true;
268            }
269        } else if (isZero(a) && isZero(d)) {
270            flags |= ROT_90;
271            if (b>0)    flags |= FLIP_V;
272            if (c<0)    flags |= FLIP_H;
273            if (!absIsOne(b) || !absIsOne(c)) {
274                scale = true;
275            }
276        } else {
277            // there is a skew component and/or a non 90 degrees rotation
278            flags = ROT_INVALID;
279        }
280
281        mType = flags << 8;
282        if (flags & ROT_INVALID) {
283            mType |= UNKNOWN;
284        } else {
285            if ((flags & ROT_90) || ((flags & ROT_180) == ROT_180))
286                mType |= ROTATE;
287            if (flags & FLIP_H)
288                mType ^= SCALE;
289            if (flags & FLIP_V)
290                mType ^= SCALE;
291            if (scale)
292                mType |= SCALE;
293        }
294
295        if (!isZero(x) || !isZero(y))
296            mType |= TRANSLATE;
297    }
298    return mType;
299}
300
301uint32_t Transform::getType() const {
302    return type() & 0xFF;
303}
304
305uint32_t Transform::getOrientation() const
306{
307    return (type() >> 8) & 0xFF;
308}
309
310bool Transform::preserveRects() const
311{
312    return (getOrientation() & ROT_INVALID) ? false : true;
313}
314
315void Transform::dump(const char* name) const
316{
317    type(); // updates the type
318
319    String8 flags, type;
320    const mat33& m(mMatrix);
321    uint32_t orient = mType >> 8;
322
323    if (orient&ROT_INVALID) {
324        flags.append("ROT_INVALID ");
325    } else {
326        if (orient&ROT_90) {
327            flags.append("ROT_90 ");
328        } else {
329            flags.append("ROT_0 ");
330        }
331        if (orient&FLIP_V)
332            flags.append("FLIP_V ");
333        if (orient&FLIP_H)
334            flags.append("FLIP_H ");
335    }
336
337    if (!(mType&(SCALE|ROTATE|TRANSLATE)))
338        type.append("IDENTITY ");
339    if (mType&SCALE)
340        type.append("SCALE ");
341    if (mType&ROTATE)
342        type.append("ROTATE ");
343    if (mType&TRANSLATE)
344        type.append("TRANSLATE ");
345
346    ALOGD("%s 0x%08x (%s, %s)", name, mType, flags.string(), type.string());
347    ALOGD("%.4f  %.4f  %.4f", m[0][0], m[1][0], m[2][0]);
348    ALOGD("%.4f  %.4f  %.4f", m[0][1], m[1][1], m[2][1]);
349    ALOGD("%.4f  %.4f  %.4f", m[0][2], m[1][2], m[2][2]);
350}
351
352// ---------------------------------------------------------------------------
353
354}; // namespace android
355