Better PFM support.

imageio/imageio-core/src/main/java/com/twelvemonkeys/imageio/util/IIOUtil.java

@@ -291,4 +291,21 @@ public final class IIOUtil {
             System.arraycopy(srcRow, srcPos + x, destRow, destPos + x / samplePeriod, pixelStride);
         }
     }
+
+    public static void subsampleRow(float[] srcRow, int srcPos, int srcWidth,
+                                    float[] destRow, int destPos,
+                                    int samplesPerPixel, int bitsPerSample, int samplePeriod) {
+        Validate.isTrue(samplePeriod > 1, "samplePeriod must be > 1"); // Period == 1 could be a no-op...
+        Validate.isTrue(bitsPerSample > 0 && bitsPerSample <= 32 && (bitsPerSample == 1 || bitsPerSample % 2 == 0),
+                "bitsPerSample must be > 0 and <= 32 and a power of 2");
+        Validate.isTrue(samplesPerPixel > 0, "samplesPerPixel must be > 0");
+        Validate.isTrue(samplesPerPixel * bitsPerSample <= 32 || samplesPerPixel * bitsPerSample % 32 == 0,
+                "samplesPerPixel * bitsPerSample must be < 32 or a multiple of 32 ");
+
+        int pixelStride = bitsPerSample * samplesPerPixel / 32;
+        for (int x = 0; x < srcWidth * pixelStride; x += samplePeriod * pixelStride) {
+            // System.arraycopy should be intrinsic, but consider using direct array access for pixelStride == 1
+            System.arraycopy(srcRow, srcPos + x, destRow, destPos + x / samplePeriod, pixelStride);
+        }
+    }
 }

imageio/imageio-pnm/src/main/java/com/twelvemonkeys/imageio/plugins/pnm/PNMHeader.java

@@ -45,6 +45,7 @@ final class PNMHeader {
     private final TupleType tupleType;
     private final int width;
     private final int height;
+    private final float maxSampleFloat;
     private final int maxSample;
 
     private final List<String> comments;
@@ -57,6 +58,7 @@ final class PNMHeader {
         this.height = isTrue(height > 0, height, "height must be greater than: %d");
         isTrue(depth == tupleType.getSamplesPerPixel(), depth, String.format("incorrect depth for %s, expected %d: %d", tupleType, tupleType.getSamplesPerPixel(), depth));
         this.maxSample = isTrue(tupleType.isValidMaxSample(maxSample), maxSample, "maxSample out of range: %d");
+        this.maxSampleFloat = this.maxSample;
 
         this.comments = Collections.unmodifiableList(new ArrayList<String>(comments));
 
@@ -70,7 +72,8 @@ final class PNMHeader {
         this.height = isTrue(height > 0, height, "height must be greater than: %d");
         isTrue(depth == tupleType.getSamplesPerPixel(), depth, String.format("incorrect depth for %s, expected %d: %d", tupleType, tupleType.getSamplesPerPixel(), depth));
 
-        this.maxSample = -1;
+        this.maxSample = 1;
+        this.maxSampleFloat = maxSample;
         this.byteOrder = byteOrder;
 
         this.comments = Collections.unmodifiableList(new ArrayList<String>(comments));
@@ -118,11 +121,8 @@ final class PNMHeader {
         if (maxSample <= PNM.MAX_VAL_16BIT) {
             return 16;
         }
-        if ((maxSample & 0xffffffffL) <= PNM.MAX_VAL_32BIT) {
-            return 32;
-        }
 
-        throw new AssertionError("maxSample exceeds 32 bit");
+        return 32;
     }
 
     public int getTransferType() {
@@ -135,11 +135,8 @@ final class PNMHeader {
         if (maxSample <= PNM.MAX_VAL_16BIT) {
             return DataBuffer.TYPE_USHORT;
         }
-        if ((maxSample & 0xffffffffL) <= PNM.MAX_VAL_32BIT) {
-            return DataBuffer.TYPE_INT;
-        }
 
-        throw new AssertionError("maxSample exceeds 32 bit");
+        return DataBuffer.TYPE_INT;
     }
 
     public List<String> getComments() {

imageio/imageio-pnm/src/main/java/com/twelvemonkeys/imageio/plugins/pnm/PNMImageReader.java

@@ -49,11 +49,13 @@ import java.io.DataInput;
 import java.io.DataInputStream;
 import java.io.File;
 import java.io.IOException;
-import java.nio.charset.Charset;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
 
+import static com.twelvemonkeys.imageio.util.IIOUtil.subsampleRow;
+
 public final class PNMImageReader extends ImageReaderBase {
     // TODO: Allow reading unknown tuple types as Raster!
     // TODO: readAsRenderedImage?
@@ -83,7 +85,7 @@ public final class PNMImageReader extends ImageReaderBase {
 
     static String asASCII(final short type) {
         byte[] asciiBytes = {(byte) ((type >> 8) & 0xff), (byte) (type & 0xff)};
-        return new String(asciiBytes, Charset.forName("ASCII"));
+        return new String(asciiBytes, StandardCharsets.US_ASCII);
     }
 
     @Override
@@ -150,7 +152,6 @@ public final class PNMImageReader extends ImageReaderBase {
 
             default:
                 // TODO: Allow reading unknown tuple types as Raster!
-
                 throw new AssertionError("Unknown PNM tuple type: " + header.getTupleType());
         }
     }
@@ -261,7 +262,7 @@ public final class PNMImageReader extends ImageReaderBase {
         for (int y = 0; y < height; y++) {
             switch (transferType) {
                 case DataBuffer.TYPE_BYTE:
-                    readRowByte(destRaster, clippedRow, colorConvert, rowDataByte, samplesPerPixel, input, y, srcRegion, xSub, ySub);
+                    readRowByte(destRaster, clippedRow, colorConvert, rowDataByte, header.getBitsPerSample(), samplesPerPixel, input, y, srcRegion, xSub, ySub);
                     break;
                 case DataBuffer.TYPE_USHORT:
                     readRowUShort(destRaster, clippedRow, rowDataUShort, samplesPerPixel, input, y, srcRegion, xSub, ySub);
@@ -339,7 +340,7 @@ public final class PNMImageReader extends ImageReaderBase {
                              Raster rowRaster,
                              final ColorConvertOp colorConvert,
                              final byte[] rowDataByte,
-                             final int samplesPerPixel,
+                             final int bitsPerSample, final int samplesPerPixel,
                              final DataInput input, final int y,
                              final Rectangle srcRegion,
                              final int xSub, final int ySub) throws IOException {
@@ -352,7 +353,9 @@ public final class PNMImageReader extends ImageReaderBase {
         input.readFully(rowDataByte);
 
         // Subsample (horizontal)
-        subsampleHorizontal(rowDataByte, rowDataByte.length, samplesPerPixel, xSub);
+        if (xSub > 1) {
+            subsampleRow(rowDataByte, srcRegion.x, srcRegion.width, rowDataByte, 0, samplesPerPixel, bitsPerSample, xSub);
+        }
 
         normalize(rowDataByte, 0, rowDataByte.length / xSub);
 
@@ -379,7 +382,9 @@ public final class PNMImageReader extends ImageReaderBase {
         readFully(input, rowDataUShort);
 
         // Subsample (horizontal)
-        subsampleHorizontal(rowDataUShort, rowDataUShort.length, samplesPerPixel, xSub);
+        if (xSub > 1) {
+            subsampleRow(rowDataUShort, srcRegion.x, srcRegion.width, rowDataUShort, 0, samplesPerPixel, 16, xSub);
+        }
 
         normalize(rowDataUShort);
 
@@ -402,11 +407,14 @@ public final class PNMImageReader extends ImageReaderBase {
         readFully(input, rowDataFloat);
 
         // Subsample (horizontal)
-        subsampleHorizontal(rowDataFloat, rowDataFloat.length, samplesPerPixel, xSub);
+        if (xSub > 1) {
+            subsampleRow(rowDataFloat, srcRegion.x, srcRegion.width, rowDataFloat, 0, samplesPerPixel, 32, xSub);
+        }
 
         normalize(rowDataFloat);
 
-        int destY = (y - srcRegion.y) / ySub;
+        // Note: PFM is stored bottom to top!
+        int destY = destRaster.getHeight() - 1 - (y - srcRegion.y) / ySub;
         // TODO: ColorConvertOp if needed
         destRaster.setDataElements(0, destY, rowRaster);
     }
@@ -437,19 +445,6 @@ public final class PNMImageReader extends ImageReaderBase {
         }
     }
 
-    @SuppressWarnings("SuspiciousSystemArraycopy")
-    private void subsampleHorizontal(final Object data, final int length, final int samplesPerPixel, final int xSub) {
-        if (xSub == 1) {
-            return;
-        }
-
-        // TODO: Super-special 1 bit subsampling handling for PBM
-
-        for (int x = 0; x < length / xSub; x += samplesPerPixel) {
-            System.arraycopy(data, x * xSub, data, x, samplesPerPixel);
-        }
-    }
-
     private void normalize(final byte[] rowData, final int start, final int length) {
         switch (header.getTupleType()) {
             case BLACKANDWHITE:
@@ -484,13 +479,9 @@ public final class PNMImageReader extends ImageReaderBase {
     }
 
     private void normalize(final float[] rowData) {
-        // TODO: Do the real thing, find min/max and normalize to range 0...255? But only if not reading raster..? Only support reading as raster?
         // Normalize
         for (int i = 0; i < rowData.length; i++) {
-//            if (rowData[i] > 275f /*header.getMaxSampleFloat()*/) {
+            rowData[i] = Math.min(1, rowData[i]); // Clamp
-//                System.out.println("rowData[" + i + "]: " + rowData[i]);
-//            }
-//            rowData[i] = rowData[i] / 275f /*header.getMaxSampleFloat()*/;
         }
     }
 

imageio/imageio-pnm/src/main/java/com/twelvemonkeys/imageio/plugins/pnm/PNMMetadata.java

@@ -151,7 +151,10 @@ final class PNMMetadata extends AbstractMetadata {
         IIOMetadataNode dimension = new IIOMetadataNode("Dimension");
 
         IIOMetadataNode imageOrientation = new IIOMetadataNode("ImageOrientation");
-        imageOrientation.setAttribute("value", "Normal");
+        imageOrientation.setAttribute("value",
+                header.getFileType() == PNM.PFM_GRAY || header.getFileType() == PNM.PFM_RGB
+                ? "FlipH"
+                : "Normal");
         dimension.appendChild(imageOrientation);
 
         return dimension;