From 2223579dfee2b40c5a483f087949a1ee3d49cd60 Mon Sep 17 00:00:00 2001
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Date: Sat, 2 May 2020 21:45:56 +0300
Subject: qcam: dng_writer: Generate thumbnail in RGB format
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While the DNG specification supports greyscale ("BlackIsZero") for
thumbnails, RawTherapee seems to have trouble reading them. Generate
thumbnails in RGB instead (but still with greyscale content, to avoid
having to interpolate colour components).
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
---
src/qcam/dng_writer.cpp | 14 +++++++++-----
1 file changed, 9 insertions(+), 5 deletions(-)
(limited to 'src/qcam')
diff --git a/src/qcam/dng_writer.cpp b/src/qcam/dng_writer.cpp
index d04a8e16..bc1a63e6 100644
--- a/src/qcam/dng_writer.cpp
+++ b/src/qcam/dng_writer.cpp
@@ -74,7 +74,10 @@ void thumbScanlineSBGGRxxP(const FormatInfo &info, void *output,
unsigned int skip = info.bitsPerSample * 16 / 8;
for (unsigned int x = 0; x < width; x++) {
- *out++ = (in[0] + in[1] + in[stride] + in[stride + 1]) >> 2;
+ uint8_t value = (in[0] + in[1] + in[stride] + in[stride + 1]) >> 2;
+ *out++ = value;
+ *out++ = value;
+ *out++ = value;
in += skip;
}
}
@@ -175,16 +178,17 @@ int DNGWriter::write(const char *filename, const Camera *camera,
TIFFSetField(tif, TIFFTAG_ORIENTATION, ORIENTATION_TOPLEFT);
/*
- * Thumbnail-specific tags. The thumbnail is stored as a greyscale image
- * with 1/16 of the raw image resolution.
+ * Thumbnail-specific tags. The thumbnail is stored as an RGB image
+ * with 1/16 of the raw image resolution. Greyscale would save space,
+ * but doesn't seem well supported by RawTherapee.
*/
TIFFSetField(tif, TIFFTAG_SUBFILETYPE, FILETYPE_REDUCEDIMAGE);
TIFFSetField(tif, TIFFTAG_IMAGEWIDTH, config.size.width / 16);
TIFFSetField(tif, TIFFTAG_IMAGELENGTH, config.size.height / 16);
TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, 8);
TIFFSetField(tif, TIFFTAG_COMPRESSION, COMPRESSION_NONE);
- TIFFSetField(tif, TIFFTAG_PHOTOMETRIC, PHOTOMETRIC_MINISBLACK);
- TIFFSetField(tif, TIFFTAG_SAMPLESPERPIXEL, 1);
+ TIFFSetField(tif, TIFFTAG_PHOTOMETRIC, PHOTOMETRIC_RGB);
+ TIFFSetField(tif, TIFFTAG_SAMPLESPERPIXEL, 3);
TIFFSetField(tif, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG);
TIFFSetField(tif, TIFFTAG_SAMPLEFORMAT, SAMPLEFORMAT_UINT);
--
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