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