1069             return;
1070         }
1071 
1072         // Backwards map from destination pixels
1073         // (dstX = updateMinX + k*updateXStep)
1074         // to source pixels (sourceX), and then
1075         // to offset and skip in passRow (srcX and srcXStep)
1076         int sourceX =
1077             (updateMinX - destinationOffset.x)*sourceXSubsampling +
1078             sourceRegion.x;
1079         int srcX = (sourceX - xStart)/xStep;
1080 
1081         // Compute the step factor in the source
1082         int srcXStep = updateXStep*sourceXSubsampling/xStep;
1083 
1084         byte[] byteData = null;
1085         short[] shortData = null;
1086         byte[] curr = new byte[bytesPerRow];
1087         byte[] prior = new byte[bytesPerRow];
1088 


1089         // Create a 1-row tall Raster to hold the data
1090         WritableRaster passRow = createRaster(passWidth, 1, inputBands,
1091                                               eltsPerRow,
1092                                               bitDepth);









1093 
1094         // Create an array suitable for holding one pixel
1095         int[] ps = passRow.getPixel(0, 0, (int[])null);
1096 
1097         DataBuffer dataBuffer = passRow.getDataBuffer();
1098         int type = dataBuffer.getDataType();
1099         if (type == DataBuffer.TYPE_BYTE) {
1100             byteData = ((DataBufferByte)dataBuffer).getData();
1101         } else {
1102             shortData = ((DataBufferUShort)dataBuffer).getData();
1103         }
1104 
1105         processPassStarted(theImage,
1106                            passNum,
1107                            sourceMinProgressivePass,
1108                            sourceMaxProgressivePass,
1109                            updateMinX, updateMinY,
1110                            updateXStep, updateYStep,
1111                            destinationBands);
1112 

1069             return;
1070         }
1071 
1072         // Backwards map from destination pixels
1073         // (dstX = updateMinX + k*updateXStep)
1074         // to source pixels (sourceX), and then
1075         // to offset and skip in passRow (srcX and srcXStep)
1076         int sourceX =
1077             (updateMinX - destinationOffset.x)*sourceXSubsampling +
1078             sourceRegion.x;
1079         int srcX = (sourceX - xStart)/xStep;
1080 
1081         // Compute the step factor in the source
1082         int srcXStep = updateXStep*sourceXSubsampling/xStep;
1083 
1084         byte[] byteData = null;
1085         short[] shortData = null;
1086         byte[] curr = new byte[bytesPerRow];
1087         byte[] prior = new byte[bytesPerRow];
1088 
1089         WritableRaster passRow = null;
1090         try {
1091             // Create a 1-row tall Raster to hold the data
1092             passRow = createRaster(passWidth, 1, inputBands, eltsPerRow,

1093                                    bitDepth);
1094         } catch (Exception e) {
1095             /*
1096              * createRaster() can throw many types of Exception but according
1097              * to specification we must throw only IIOException if we face any
1098              * issue while reading an image. So at this high level we catch
1099              * the exception and wrap it around IIOException.
1100              */
1101             throw new IIOException("Caught exception during read: ", e);
1102         }
1103 
1104         // Create an array suitable for holding one pixel
1105         int[] ps = passRow.getPixel(0, 0, (int[])null);
1106 
1107         DataBuffer dataBuffer = passRow.getDataBuffer();
1108         int type = dataBuffer.getDataType();
1109         if (type == DataBuffer.TYPE_BYTE) {
1110             byteData = ((DataBufferByte)dataBuffer).getData();
1111         } else {
1112             shortData = ((DataBufferUShort)dataBuffer).getData();
1113         }
1114 
1115         processPassStarted(theImage,
1116                            passNum,
1117                            sourceMinProgressivePass,
1118                            sourceMaxProgressivePass,
1119                            updateMinX, updateMinY,
1120                            updateXStep, updateYStep,
1121                            destinationBands);
1122