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- /*
- * Copyright 2012 ZXing authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
- #import "ZXPerspectiveTransform.h"
-
- @interface ZXPerspectiveTransform ()
-
- @property (nonatomic, assign, readonly) float a11;
- @property (nonatomic, assign, readonly) float a12;
- @property (nonatomic, assign, readonly) float a13;
- @property (nonatomic, assign, readonly) float a21;
- @property (nonatomic, assign, readonly) float a22;
- @property (nonatomic, assign, readonly) float a23;
- @property (nonatomic, assign, readonly) float a31;
- @property (nonatomic, assign, readonly) float a32;
- @property (nonatomic, assign, readonly) float a33;
-
- @end
-
- @implementation ZXPerspectiveTransform
-
- - (id)initWithA11:(float)a11 a21:(float)a21 a31:(float)a31 a12:(float)a12 a22:(float)a22 a32:(float)a32 a13:(float)a13 a23:(float)a23 a33:(float)a33 {
- if (self = [super init]) {
- _a11 = a11;
- _a12 = a12;
- _a13 = a13;
- _a21 = a21;
- _a22 = a22;
- _a23 = a23;
- _a31 = a31;
- _a32 = a32;
- _a33 = a33;
- }
-
- return self;
- }
-
- + (ZXPerspectiveTransform *)quadrilateralToQuadrilateral:(float)x0 y0:(float)y0 x1:(float)x1 y1:(float)y1 x2:(float)x2 y2:(float)y2 x3:(float)x3 y3:(float)y3 x0p:(float)x0p y0p:(float)y0p x1p:(float)x1p y1p:(float)y1p x2p:(float)x2p y2p:(float)y2p x3p:(float)x3p y3p:(float)y3p {
- ZXPerspectiveTransform *qToS = [self quadrilateralToSquare:x0 y0:y0 x1:x1 y1:y1 x2:x2 y2:y2 x3:x3 y3:y3];
- ZXPerspectiveTransform *sToQ = [self squareToQuadrilateral:x0p y0:y0p x1:x1p y1:y1p x2:x2p y2:y2p x3:x3p y3:y3p];
- return [sToQ times:qToS];
- }
-
- - (void)transformPoints:(float *)points pointsLen:(int)pointsLen {
- int max = pointsLen;
- for (int i = 0; i < max; i += 2) {
- float x = points[i];
- float y = points[i + 1];
- float denominator = self.a13 * x + self.a23 * y + self.a33;
- points[i] = (self.a11 * x + self.a21 * y + self.a31) / denominator;
- points[i + 1] = (self.a12 * x + self.a22 * y + self.a32) / denominator;
- }
- }
-
- /**
- * Convenience method, not optimized for performance.
- */
- - (void)transformPoints:(float *)xValues yValues:(float *)yValues pointsLen:(int)pointsLen {
- int n = pointsLen;
- for (int i = 0; i < n; i ++) {
- float x = xValues[i];
- float y = yValues[i];
- float denominator = self.a13 * x + self.a23 * y + self.a33;
- xValues[i] = (self.a11 * x + self.a21 * y + self.a31) / denominator;
- yValues[i] = (self.a12 * x + self.a22 * y + self.a32) / denominator;
- }
- }
-
- + (ZXPerspectiveTransform *)squareToQuadrilateral:(float)x0 y0:(float)y0 x1:(float)x1 y1:(float)y1 x2:(float)x2 y2:(float)y2 x3:(float)x3 y3:(float)y3 {
- float dx3 = x0 - x1 + x2 - x3;
- float dy3 = y0 - y1 + y2 - y3;
- if (dx3 == 0.0f && dy3 == 0.0f) {
- // Affine
- return [[ZXPerspectiveTransform alloc] initWithA11:x1 - x0 a21:x2 - x1 a31:x0 a12:y1 - y0 a22:y2 - y1 a32:y0 a13:0.0f a23:0.0f a33:1.0f];
- } else {
- float dx1 = x1 - x2;
- float dx2 = x3 - x2;
- float dy1 = y1 - y2;
- float dy2 = y3 - y2;
- float denominator = dx1 * dy2 - dx2 * dy1;
- float a13 = (dx3 * dy2 - dx2 * dy3) / denominator;
- float a23 = (dx1 * dy3 - dx3 * dy1) / denominator;
- return [[ZXPerspectiveTransform alloc] initWithA11:x1 - x0 + a13 * x1 a21:x3 - x0 + a23 * x3 a31:x0 a12:y1 - y0 + a13 * y1 a22:y3 - y0 + a23 * y3 a32:y0 a13:a13 a23:a23 a33:1.0f];
- }
- }
-
- + (ZXPerspectiveTransform *)quadrilateralToSquare:(float)x0 y0:(float)y0 x1:(float)x1 y1:(float)y1 x2:(float)x2 y2:(float)y2 x3:(float)x3 y3:(float)y3 {
- return [[self squareToQuadrilateral:x0 y0:y0 x1:x1 y1:y1 x2:x2 y2:y2 x3:x3 y3:y3] buildAdjoint];
- }
-
- - (ZXPerspectiveTransform *)buildAdjoint {
- return [[ZXPerspectiveTransform alloc] initWithA11:self.a22 * self.a33 - self.a23 * self.a32
- a21:self.a23 * self.a31 - self.a21 * self.a33
- a31:self.a21 * self.a32 - self.a22 * self.a31
- a12:self.a13 * self.a32 - self.a12 * self.a33
- a22:self.a11 * self.a33 - self.a13 * self.a31
- a32:self.a12 * self.a31 - self.a11 * self.a32
- a13:self.a12 * self.a23 - self.a13 * self.a22
- a23:self.a13 * self.a21 - self.a11 * self.a23
- a33:self.a11 * self.a22 - self.a12 * self.a21];
- }
-
- - (ZXPerspectiveTransform *)times:(ZXPerspectiveTransform *)other {
- return [[ZXPerspectiveTransform alloc] initWithA11:self.a11 * other.a11 + self.a21 * other.a12 + self.a31 * other.a13
- a21:self.a11 * other.a21 + self.a21 * other.a22 + self.a31 * other.a23
- a31:self.a11 * other.a31 + self.a21 * other.a32 + self.a31 * other.a33
- a12:self.a12 * other.a11 + self.a22 * other.a12 + self.a32 * other.a13
- a22:self.a12 * other.a21 + self.a22 * other.a22 + self.a32 * other.a23
- a32:self.a12 * other.a31 + self.a22 * other.a32 + self.a32 * other.a33
- a13:self.a13 * other.a11 + self.a23 * other.a12 + self.a33 * other.a13
- a23:self.a13 * other.a21 + self.a23 * other.a22 + self.a33 * other.a23
- a33:self.a13 * other.a31 + self.a23 * other.a32 + self.a33 * other.a33];
- }
-
- @end
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