--- name: "TIFFReadRGBAStrip" section: "3t" platform: "linux" package: "libtiff3g-dev" version: "3.5.5-6.woody5" release: "Debian 3.0 (Woody)" platforms: ["linux"] url: "https://new.carta.tech/TIFFReadRGBAStrip" --- # TIFFReadRGBAStrip(3t) read and decode an image strip into a fixed-format raster ## NAME TIFFReadRGBAStrip - read and decode an image strip into a fixed-format raster ## SYNOPSIS ``` #include #define TIFFGetR(abgr) ((abgr) & 0xff) #define TIFFGetG(abgr) (((abgr) >> 8) & 0xff) #define TIFFGetB(abgr) (((abgr) >> 16) & 0xff) #define TIFFGetA(abgr) (((abgr) >> 24) & 0xff) int TIFFReadRGBAStrip(TIFF* tif, tstrip_t strip, uint32 * raster ) ``` ## DESCRIPTION *TIFFReadRGBAStrip* reads a single strip of a strip-based image into memory, storing the result in the user supplied RGBA *raster*. The raster is assumed to be an array of width times rowsperstrip 32-bit entries, where width is the width of the image (TIFFTAG\_IMAGEWIDTH) and rowsperstrip is the maximum lines in a strip (TIFFTAG\_ROWSPERSTRIP). The *strip* value should be the strip number (strip zero is the first) as returned by the *TIFFComputeStrip* function, but always for sample 0. Note that the raster is assume to be organized such that the pixel at location (*x*,*y*) is *raster*\[*y*\**width*+*x*\]; with the raster origin in the *lower-left hand corner* of the strip. That is bottom to top organization. When reading a partial last strip in the file the last line of the image will begin at the beginning of the buffer. Raster pixels are 8-bit packed red, green, blue, alpha samples. The macros *TIFFGetR*, *TIFFGetG*, *TIFFGetB*, and *TIFFGetA* should be used to access individual samples. Images without Associated Alpha matting information have a constant Alpha of 1.0 (255). See the *TIFFRGBAImage*(3T) page for more details on how various image types are converted to RGBA values. ## NOTES Samples must be either 1, 2, 4, 8, or 16 bits. Colorimetric samples/pixel must be either 1, 3, or 4 (i.e. *SamplesPerPixel* minus *ExtraSamples*). Palette image colormaps that appear to be incorrectly written as 8-bit values are automatically scaled to 16-bits. *TIFFReadRGBAStrip* is just a wrapper around the more general *TIFFRGBAImage*(3T) facilities. It's main advantage over the similar *TIFFReadRGBAImage()* function is that for large images a single buffer capable of holding the whole image doesn't need to be allocated, only enough for one strip. The *TIFFReadRGBATile()* function does a similar operation for tiled images. ## RETURN VALUES 1 is returned if the image was successfully read and converted. Otherwise, 0 is returned if an error was encountered. ## DIAGNOSTICS All error messages are directed to the *TIFFError*(3T) routine. **Sorry, can not handle %d-bit pictures**. The image had *BitsPerSample* other than 1, 2, 4, 8, or 16. **Sorry, can not handle %d-channel images**. The image had *SamplesPerPixel* other than 1, 3, or 4. **Missing needed "PhotometricInterpretation" tag**. The image did not have a tag that describes how to display the data. **No "PhotometricInterpretation" tag, assuming RGB**. The image was missing a tag that describes how to display it, but because it has 3 or 4 samples/pixel, it is assumed to be RGB. **No "PhotometricInterpretation" tag, assuming min-is-black**. The image was missing a tag that describes how to display it, but because it has 1 sample/pixel, it is assumed to be a grayscale or bilevel image. **No space for photometric conversion table**. There was insufficient memory for a table used to convert image samples to 8-bit RGB. **Missing required "Colormap" tag**. A Palette image did not have a required *Colormap* tag. **No space for tile buffer**. There was insufficient memory to allocate an i/o buffer. **No space for strip buffer**. There was insufficient memory to allocate an i/o buffer. **Can not handle format**. The image has a format (combination of *BitsPerSample*, *SamplesPerPixel*, and *PhotometricInterpretation*) that *TIFFReadRGBAImage* can not handle. **No space for B&W mapping table**. There was insufficient memory to allocate a table used to map grayscale data to RGB. **No space for Palette mapping table**. There was insufficient memory to allocate a table used to map data to 8-bit RGB. ## BUGS Orientations other than bottom-left, or top-left are not handled correctly. ## SEE ALSO *libtiff*(3T), *TIFFOpen*(3T), *TIFFRGBAImage*(3T), *TIFFReadRGBAImage*(3T), *TIFFReadRGBATile*(3T)