/*
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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 "ZXByteArray.h"
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#import "ZXRGBLuminanceSource.h"
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@interface ZXRGBLuminanceSource ()
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@property (nonatomic, strong, readonly) ZXByteArray *luminances;
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@property (nonatomic, assign, readonly) int dataWidth;
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@property (nonatomic, assign, readonly) int dataHeight;
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@property (nonatomic, assign, readonly) int left;
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@property (nonatomic, assign, readonly) int top;
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@end
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@implementation ZXRGBLuminanceSource
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- (id)initWithWidth:(int)width height:(int)height pixels:(int *)pixels pixelsLen:(int)pixelsLen {
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if (self = [super initWithWidth:width height:height]) {
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_dataWidth = width;
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_dataHeight = height;
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_left = 0;
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_top = 0;
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// In order to measure pure decoding speed, we convert the entire image to a greyscale array
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// up front, which is the same as the Y channel of the YUVLuminanceSource in the real app.
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_luminances = [[ZXByteArray alloc] initWithLength:width * height];
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for (int y = 0; y < height; y++) {
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int offset = y * width;
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for (int x = 0; x < width; x++) {
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int pixel = pixels[offset + x];
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int r = (pixel >> 16) & 0xff;
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int g = (pixel >> 8) & 0xff;
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int b = pixel & 0xff;
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if (r == g && g == b) {
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// Image is already greyscale, so pick any channel.
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_luminances.array[offset + x] = (int8_t) r;
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} else {
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// Calculate luminance cheaply, favoring green.
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_luminances.array[offset + x] = (int8_t) ((r + g + g + b) / 4);
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}
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}
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}
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}
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return self;
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}
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- (id)initWithPixels:(ZXByteArray *)pixels dataWidth:(int)dataWidth dataHeight:(int)dataHeight
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left:(int)left top:(int)top width:(int)width height:(int)height {
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if (self = [super initWithWidth:width height:height]) {
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if (left + self.width > dataWidth || top + self.height > dataHeight) {
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[NSException raise:NSInvalidArgumentException format:@"Crop rectangle does not fit within image data."];
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}
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_luminances = pixels;
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_dataWidth = dataWidth;
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_dataHeight = dataHeight;
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_left = left;
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_top = top;
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}
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return self;
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}
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- (ZXByteArray *)rowAtY:(int)y row:(ZXByteArray *)row {
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if (y < 0 || y >= self.height) {
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[NSException raise:NSInvalidArgumentException format:@"Requested row is outside the image: %d", y];
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}
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int width = self.width;
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if (!row || row.length < width) {
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row = [[ZXByteArray alloc] initWithLength:width];
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}
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int offset = (y + self.top) * self.dataWidth + self.left;
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memcpy(row.array, self.luminances.array + offset, self.width * sizeof(int8_t));
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return row;
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}
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- (ZXByteArray *)matrix {
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int width = self.width;
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int height = self.height;
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// If the caller asks for the entire underlying image, save the copy and give them the
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// original data. The docs specifically warn that result.length must be ignored.
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if (width == self.dataWidth && height == self.dataHeight) {
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return self.luminances;
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}
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int area = self.width * self.height;
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ZXByteArray *matrix = [[ZXByteArray alloc] initWithLength:area];
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int inputOffset = self.top * self.dataWidth + self.left;
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// If the width matches the full width of the underlying data, perform a single copy.
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if (self.width == self.dataWidth) {
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memcpy(matrix.array, self.luminances.array + inputOffset, (area - inputOffset) * sizeof(int8_t));
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return matrix;
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}
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// Otherwise copy one cropped row at a time.
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for (int y = 0; y < self.height; y++) {
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int outputOffset = y * self.width;
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memcpy(matrix.array + outputOffset, self.luminances.array + inputOffset, self.width * sizeof(int8_t));
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inputOffset += self.dataWidth;
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}
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return matrix;
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}
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- (BOOL)cropSupported {
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return YES;
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}
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- (ZXLuminanceSource *)crop:(int)left top:(int)top width:(int)width height:(int)height {
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return [[[self class] alloc] initWithPixels:self.luminances
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dataWidth:self.dataWidth
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dataHeight:self.dataHeight
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left:self.left + left
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top:self.top + top
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width:width
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height:height];
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}
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@end
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