Changes between Version 2 and Version 3 of rfc15_nodatabitmask
- Timestamp:
- Aug 9, 2007, 1:12:15 PM (17 years ago)
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rfc15_nodatabitmask
v2 v3 20 20 }}} 21 21 22 Note that the GetNullMask() should always return a GDALRasterBand mask, even if it is only an all 255 mask with thetype22 Note that the !GetNullMask() should always return a GDALRasterBand mask, even if it is only an all 255 mask with thetype 23 23 24 24 The GDALNullMaskType enumeration has the following values: … … 28 28 * GDALNMTPerDataset: The mask band is meaningful and is shared between all bands on this dataset. 29 29 30 Note that the GetNullMask() should always return a GDALRasterBand mask, even if it is only an all 255 mask with the type set to GDALNMTAllValid.30 Note that the !GetNullMask() should always return a GDALRasterBand mask, even if it is only an all 255 mask with the type set to GDALNMTAllValid. 31 31 32 32 == Default Implementation == 33 33 34 The GDALRasterBand class will include a default implementation of GetNullMask() that returns one of two default implementations. The first default implement is a GDALNMTAllValid band that returns all 255. The second default implementation would return a mask computed by reading the imagery data and comparing it to the nodata value. The nodata based one would be used when the base band has a nodata value.34 The GDALRasterBand class will include a default implementation of !GetNullMask() that returns one of two default implementations. The first default implement is a GDALNMTAllValid band that returns all 255. The second default implementation would return a mask computed by reading the imagery data and comparing it to the nodata value. The nodata based one would be used when the base band has a nodata value. 35 35 36 36 == Drivers Updated == … … 57 57 == Issues == 58 58 59 I'm tempted to change GetNullMaskType() intoGetNullMaskFlags() and have the result be an or-ed set of flags. It would allow us to differentiate mask bands auto generated from nodata, and add special interpretations in the future, like is-alpha or is-confidence.59 I'm tempted to change !GetNullMaskType() into !GetNullMaskFlags() and have the result be an or-ed set of flags. It would allow us to differentiate mask bands auto generated from nodata, and add special interpretations in the future, like is-alpha or is-confidence. 60 60 61 61 * I haven't filled in how creation of masks works.
