--- /dev/null
+/*\r
+* Licensed under the Apache License, Version 2.0 (the "License");\r
+* you may not use this file except in compliance with the License.\r
+* You may obtain a copy of the License at\r
+*\r
+* http://www.apache.org/licenses/LICENSE-2.0\r
+*\r
+* Unless required by applicable law or agreed to in writing, software\r
+* distributed under the License is distributed on an "AS IS" BASIS,\r
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\r
+* See the License for the specific language governing permissions and\r
+* limitations under the License.\r
+*/\r
+\r
+using System;\r
+using BitArray = com.google.zxing.common.BitArray;\r
+using com.google.zxing.common;\r
+namespace com.google.zxing\r
+{\r
+ /**\r
+ * @author dswitkin@google.com (Daniel Switkin)\r
+ */\r
+ public abstract class BaseMonochromeBitmapSource: MonochromeBitmapSource \r
+ {\r
+ private static int LUMINANCE_BITS = 5;\r
+ private static int LUMINANCE_SHIFT = 8 - LUMINANCE_BITS;\r
+ private static int LUMINANCE_BUCKETS = 1 << LUMINANCE_BITS;\r
+\r
+ private int blackPoint;\r
+ private BlackPointEstimationMethod lastMethod;\r
+ private int lastArgument;\r
+ private int[] luminances;\r
+\r
+ protected BaseMonochromeBitmapSource() {\r
+ blackPoint = 0x7F;\r
+ lastMethod = null;\r
+ lastArgument = 0;\r
+ }\r
+\r
+ private void initLuminances() {\r
+ if (luminances == null) {\r
+ int width = getWidth();\r
+ int height = getHeight();\r
+ int max = width > height ? width : height;\r
+ luminances = new int[max];\r
+ }\r
+ }\r
+\r
+ public bool isBlack(int x, int y) {\r
+ return getLuminance(x, y) < blackPoint;\r
+ }\r
+\r
+ public BitArray getBlackRow(int y, BitArray row, int startX, int getWidth) {\r
+ if (row == null || row.getSize() < getWidth) {\r
+ row = new BitArray(getWidth);\r
+ } else {\r
+ row.clear();\r
+ }\r
+\r
+ // Reuse the same int array each time\r
+ initLuminances();\r
+ luminances = getLuminanceRow(y, luminances);\r
+\r
+ // If the current decoder calculated the blackPoint based on one row, assume we're trying to\r
+ // decode a 1D barcode, and apply some sharpening.\r
+ if (lastMethod.Equals(BlackPointEstimationMethod.ROW_SAMPLING)) {\r
+ int left = luminances[startX];\r
+ int center = luminances[startX + 1];\r
+ for (int x = 1; x < getWidth - 1; x++) {\r
+ int right = luminances[startX + x + 1];\r
+ // Simple -1 4 -1 box filter with a weight of 2\r
+ int luminance = ((center << 2) - left - right) >> 1;\r
+ if (luminance < blackPoint) {\r
+ row.set(x);\r
+ }\r
+ left = center;\r
+ center = right;\r
+ }\r
+ } else {\r
+ for (int x = 0; x < getWidth; x++) {\r
+ if (luminances[startX + x] < blackPoint) {\r
+ row.set(x);\r
+ }\r
+ }\r
+ }\r
+ return row;\r
+ }\r
+\r
+ public BitArray getBlackColumn(int x, BitArray column, int startY, int getHeight) {\r
+ if (column == null || column.getSize() < getHeight) {\r
+ column = new BitArray(getHeight);\r
+ } else {\r
+ column.clear();\r
+ }\r
+\r
+ // Reuse the same int array each time\r
+ initLuminances();\r
+ luminances = getLuminanceColumn(x, luminances);\r
+\r
+ // We don't handle "row sampling" specially here\r
+ for (int y = 0; y < getHeight; y++) {\r
+ if (luminances[startY + y] < blackPoint) {\r
+ column.set(y);\r
+ }\r
+ }\r
+ return column;\r
+ }\r
+\r
+ public void estimateBlackPoint(BlackPointEstimationMethod method, int argument){\r
+ if (!method.Equals(lastMethod) || argument != lastArgument) {\r
+ int width = getWidth();\r
+ int height = getHeight();\r
+ int[] histogram = new int[LUMINANCE_BUCKETS];\r
+ if (method.Equals(BlackPointEstimationMethod.TWO_D_SAMPLING)) {\r
+ int minDimension = width < height ? width : height;\r
+ int startX = (width - minDimension) >> 1;\r
+ int startY = (height - minDimension) >> 1;\r
+ for (int n = 0; n < minDimension; n++) {\r
+ int luminance = getLuminance(startX + n, startY + n);\r
+ histogram[luminance >> LUMINANCE_SHIFT]++;\r
+ }\r
+ } else if (method.Equals(BlackPointEstimationMethod.ROW_SAMPLING)) {\r
+ if (argument < 0 || argument >= height) {\r
+ throw new Exception("Row is not within the image: " + argument);\r
+ }\r
+ initLuminances();\r
+ luminances = getLuminanceRow(argument, luminances);\r
+ for (int x = 0; x < width; x++) {\r
+ histogram[luminances[x] >> LUMINANCE_SHIFT]++;\r
+ }\r
+ } else {\r
+ throw new Exception("Unknown method: " + method);\r
+ }\r
+ blackPoint = BlackPointEstimator.estimate(histogram) << LUMINANCE_SHIFT;\r
+ lastMethod = method;\r
+ lastArgument = argument;\r
+ }\r
+ }\r
+\r
+ public BlackPointEstimationMethod getLastEstimationMethod() {\r
+ return lastMethod;\r
+ }\r
+\r
+ public MonochromeBitmapSource rotateCounterClockwise() {\r
+ throw new Exception("Rotate not supported");\r
+ }\r
+\r
+ public bool isRotateSupported() {\r
+ return false;\r
+ }\r
+\r
+ // These two methods should not need to exist because they are defined in the interface that\r
+ // this abstract class implements. However this seems to cause problems on some Nokias. \r
+ // So we write these redundant declarations.\r
+\r
+ public abstract int getHeight();\r
+\r
+ public abstract int getWidth();\r
+\r
+ /**\r
+ * Retrieves the luminance at the pixel x,y in the bitmap. This method is only used for estimating\r
+ * the black point and implementing getBlackRow() - it is not meant for decoding, hence it is not\r
+ * part of MonochromeBitmapSource itself, and is protected.\r
+ *\r
+ * @param x The x coordinate in the image.\r
+ * @param y The y coordinate in the image.\r
+ * @return The luminance value between 0 and 255.\r
+ */\r
+ protected abstract int getLuminance(int x, int y);\r
+\r
+ /**\r
+ * This is the main mechanism for retrieving luminance data. It is dramatically more efficient\r
+ * than repeatedly calling getLuminance(). As above, this is not meant for decoders.\r
+ *\r
+ * @param y The row to fetch\r
+ * @param row The array to write luminance values into. It is <b>strongly</b> suggested that you\r
+ * allocate this yourself, making sure row.length >= getWidth(), and reuse the same\r
+ * array on subsequent calls for performance. If you pass null, you will be flogged,\r
+ * but then I will take pity on you and allocate a sufficient array internally.\r
+ * @return The array containing the luminance data. This is the same as row if it was usable.\r
+ */\r
+ protected abstract int[] getLuminanceRow(int y, int[] row);\r
+\r
+ /**\r
+ * The same as getLuminanceRow(), but for columns.\r
+ *\r
+ * @param x The column to fetch\r
+ * @param column The array to write luminance values into. See above.\r
+ * @return The array containing the luminance data.\r
+ */\r
+ protected abstract int[] getLuminanceColumn(int x, int[] column);\r
+\r
+ }\r
+}\r
+\r
+\r
projects / zxing.git / blobdiff