Image::Leptonica::Func::writefile
version 0.04
writefile.c
writefile.c High-level procedures for writing images to file: l_int32 pixaWriteFiles() l_int32 pixWrite() [behavior depends on WRITE_AS_NAMED] l_int32 pixWriteStream() l_int32 pixWriteImpliedFormat() l_int32 pixWriteTempfile() Selection of output format if default is requested l_int32 pixChooseOutputFormat() l_int32 getImpliedFileFormat() const char *getFormatExtension() Write to memory l_int32 pixWriteMem() Image display for debugging l_int32 pixDisplay() l_int32 pixDisplayWithTitle() l_int32 pixDisplayMultiple() l_int32 pixDisplayWrite() l_int32 pixDisplayWriteFormat() l_int32 pixSaveTiled() l_int32 pixSaveTiledOutline() l_int32 pixSaveTiledWithText() void l_chooseDisplayProg() Supported file formats: (1) Writing is supported without any external libraries: bmp pnm (including pbm, pgm, etc) spix (raw serialized) (2) Writing is supported with installation of external libraries: png jpg (standard jfif version) tiff (including most varieties of compression) gif webp (3) Writing is supported through special interfaces: ps (PostScript, in psio1.c, psio2.c): level 1 (uncompressed) level 2 (g4 and dct encoding: requires tiff, jpg) level 3 (g4, dct and flate encoding: requires tiff, jpg, zlib) pdf (PDF, in pdfio.c): level 1 (g4 and dct encoding: requires tiff, jpg) level 2 (g4, dct and flate encoding: requires tiff, jpg, zlib) (4) No other output formats are supported, such as jp2 (jpeg2000)
const char * getFormatExtension ( l_int32 format )
getFormatExtension() Input: format (integer) Return: extension (string), or null if format is out of range Notes: (1) This string is NOT owned by the caller; it is just a pointer to a global string. Do not free it.
l_int32 getImpliedFileFormat ( const char *filename )
getImpliedFileFormat() Input: filename Return: output format, or IFF_UNKNOWN on error or invalid extension. Notes: (1) This determines the output file format from the extension of the input filename.
l_int32 pixChooseOutputFormat ( PIX *pix )
pixChooseOutputFormat() Input: pix Return: output format, or 0 on error Notes: (1) This should only be called if the requested format is IFF_DEFAULT. (2) If the pix wasn't read from a file, its input format value will be IFF_UNKNOWN, and in that case it is written out in a compressed but lossless format.
l_int32 pixDisplay ( PIX *pixs, l_int32 x, l_int32 y )
pixDisplay() Input: pix (1, 2, 4, 8, 16, 32 bpp) x, y (location of display frame on the screen) Return: 0 if OK; 1 on error Notes: (1) This displays the image using xzgv, xli or xv on Unix, or i_view on Windows. The display program must be on your $PATH variable. It is chosen by setting the global var_DISPLAY_PROG, using l_chooseDisplayProg(). Default on Unix is xzgv. (2) Images with dimensions larger than MAX_DISPLAY_WIDTH or MAX_DISPLAY_HEIGHT are downscaled to fit those constraints. This is particulary important for displaying 1 bpp images with xv, because xv automatically downscales large images by subsampling, which looks poor. For 1 bpp, we use scale-to-gray to get decent-looking anti-aliased images. In all cases, we write a temporary file to /tmp, that is read by the display program. (3) For spp == 4, we call pixDisplayLayersRGBA() to show 3 versions of the image: the image with a fully opaque alpha, the alpha, and the image as it would appear with a white background. (4) Note: this function uses a static internal variable to number output files written by a single process. Behavior with a shared library may be unpredictable.
l_int32 pixDisplayMultiple ( const char *filepattern )
pixDisplayMultiple() Input: filepattern Return: 0 if OK; 1 on error Notes: (1) This allows display of multiple images using gthumb on unix and i_view32 on windows. The @filepattern is a regular expression that is expanded by the shell. (2) _fullpath automatically changes '/' to '\' if necessary.
l_int32 pixDisplayWithTitle ( PIX *pixs, l_int32 x, l_int32 y, const char *title, l_int32 dispflag )
pixDisplayWithTitle() Input: pix (1, 2, 4, 8, 16, 32 bpp) x, y (location of display frame) title (<optional> on frame; can be NULL); dispflag (1 to write, else disabled) Return: 0 if OK; 1 on error Notes: (1) See notes for pixDisplay(). (2) This displays the image if dispflag == 1.
l_int32 pixDisplayWrite ( PIX *pixs, l_int32 reduction )
pixDisplayWrite() Input: pix (1, 2, 4, 8, 16, 32 bpp) reduction (-1 to reset/erase; 0 to disable; otherwise this is a reduction factor) Return: 0 if OK; 1 on error Notes: (1) This defaults to jpeg output for pix that are 32 bpp or 8 bpp without a colormap. If you want to write all images losslessly, use format == IFF_PNG in pixDisplayWriteFormat(). (2) See pixDisplayWriteFormat() for usage details.
l_int32 pixDisplayWriteFormat ( PIX *pixs, l_int32 reduction, l_int32 format )
pixDisplayWriteFormat() Input: pix (1, 2, 4, 8, 16, 32 bpp) reduction (-1 to reset/erase; 0 to disable; otherwise this is a reduction factor) format (IFF_PNG or IFF_JFIF_JPEG) Return: 0 if OK; 1 on error Notes: (1) This writes files if reduction > 0. These can be displayed using pixDisplayMultiple("/tmp/display/file*"); (2) All previously written files can be erased by calling with reduction < 0; the value of pixs is ignored. (3) If reduction > 1 and depth == 1, this does a scale-to-gray reduction. (4) This function uses a static internal variable to number output files written by a single process. Behavior with a shared library may be unpredictable. (5) Output file format is as follows: format == IFF_JFIF_JPEG: png if d < 8 or d == 16 or if the output pix has a colormap. Otherwise, output is jpg. format == IFF_PNG: png (lossless) on all images. (6) For 16 bpp, the choice of full dynamic range with log scale is the best for displaying these images. Alternative outputs are pix8 = pixMaxDynamicRange(pixt, L_LINEAR_SCALE); pix8 = pixConvert16To8(pixt, 0); // low order byte pix8 = pixConvert16To8(pixt, 1); // high order byte
l_int32 pixSaveTiled ( PIX *pixs, PIXA *pixa, l_float32 scalefactor, l_int32 newrow, l_int32 space, l_int32 dp )
pixSaveTiled() Input: pixs (1, 2, 4, 8, 32 bpp) pixa (the pix are accumulated here) scalefactor (0.0 to disable; otherwise this is a scale factor) newrow (0 if placed on the same row as previous; 1 otherwise) space (horizontal and vertical spacing, in pixels) dp (depth of pixa; 8 or 32 bpp; only used on first call) Return: 0 if OK, 1 on error.
l_int32 pixSaveTiledOutline ( PIX *pixs, PIXA *pixa, l_float32 scalefactor, l_int32 newrow, l_int32 space, l_int32 linewidth, l_int32 dp )
pixSaveTiledOutline() Input: pixs (1, 2, 4, 8, 32 bpp) pixa (the pix are accumulated here) scalefactor (0.0 to disable; otherwise this is a scale factor) newrow (0 if placed on the same row as previous; 1 otherwise) space (horizontal and vertical spacing, in pixels) linewidth (width of added outline for image; 0 for no outline) dp (depth of pixa; 8 or 32 bpp; only used on first call) Return: 0 if OK, 1 on error. Notes: (1) Before calling this function for the first time, use pixaCreate() to make the @pixa that will accumulate the pix. This is passed in each time pixSaveTiled() is called. (2) @scalefactor scales the input image. After scaling and possible depth conversion, the image is saved in the input pixa, along with a box that specifies the location to place it when tiled later. Disable saving the pix by setting @scalefactor == 0.0. (3) @newrow and @space specify the location of the new pix with respect to the last one(s) that were entered. (4) @dp specifies the depth at which all pix are saved. It can be only 8 or 32 bpp. Any colormap is removed. This is only used at the first invocation. (5) This function uses two variables from call to call. If they were static, the function would not be .so or thread safe, and furthermore, there would be interference with two or more pixa accumulating images at a time. Consequently, we use the first pix in the pixa to store and obtain both the depth and the current position of the bottom (one pixel below the lowest image raster line when laid out using the boxa). The bottom variable is stored in the input format field, which is the only field available for storing an int.
l_int32 pixSaveTiledWithText ( PIX *pixs, PIXA *pixa, l_int32 outwidth, l_int32 newrow, l_int32 space, l_int32 linewidth, L_BMF *bmf, const char *textstr, l_uint32 val, l_int32 location )
pixSaveTiledWithText() Input: pixs (1, 2, 4, 8, 32 bpp) pixa (the pix are accumulated here; as 32 bpp) outwidth (in pixels; use 0 to disable entirely) newrow (1 to start a new row; 0 to go on same row as previous) space (horizontal and vertical spacing, in pixels) linewidth (width of added outline for image; 0 for no outline) bmf (<optional> font struct) textstr (<optional> text string to be added) val (color to set the text) location (L_ADD_ABOVE, L_ADD_AT_TOP, L_ADD_AT_BOT, L_ADD_BELOW) Return: 0 if OK, 1 on error. Notes: (1) Before calling this function for the first time, use pixaCreate() to make the @pixa that will accumulate the pix. This is passed in each time pixSaveTiled() is called. (2) @outwidth is the scaled width. After scaling, the image is saved in the input pixa, along with a box that specifies the location to place it when tiled later. Disable saving the pix by setting @outwidth == 0. (3) @newrow and @space specify the location of the new pix with respect to the last one(s) that were entered. (4) All pix are saved as 32 bpp RGB. (5) If both @bmf and @textstr are defined, this generates a pix with the additional text; otherwise, no text is written. (6) The text is written before scaling, so it is properly antialiased in the scaled pix. However, if the pix on different calls have different widths, the size of the text will vary. (7) See pixSaveTiledOutline() for other implementation details.
l_int32 pixWrite ( const char *filename, PIX *pix, l_int32 format )
pixWrite() Input: filename pix format (defined in imageio.h) Return: 0 if OK; 1 on error Notes: (1) Open for write using binary mode (with the "b" flag) to avoid having Windows automatically translate the NL into CRLF, which corrupts image files. On non-windows systems this flag should be ignored, per ISO C90. Thanks to Dave Bryan for pointing this out. (2) If the default image format is requested, we use the input format; if the input format is unknown, a lossless format is assigned. (3) There are two modes with respect to file naming. (a) The default code writes to @filename. (b) If WRITE_AS_NAMED is defined to 0, it's a bit fancier. Then, if @filename does not have a file extension, one is automatically appended, depending on the requested format. The original intent for providing option (b) was to insure that filenames on Windows have an extension that matches the image compression. However, this is not the default.
l_int32 pixWriteImpliedFormat ( const char *filename, PIX *pix, l_int32 quality, l_int32 progressive )
pixWriteImpliedFormat() Input: filename pix quality (iff JPEG; 1 - 100, 0 for default) progressive (iff JPEG; 0 for baseline seq., 1 for progressive) Return: 0 if OK; 1 on error Notes: (1) This determines the output format from the filename extension. (2) The last two args are ignored except for requests for jpeg files. (3) The jpeg default quality is 75.
l_int32 pixWriteMem ( l_uint8 **pdata, size_t *psize, PIX *pix, l_int32 format )
pixWriteMem() Input: &data (<return> data of tiff compressed image) &size (<return> size of returned data) pix format (defined in imageio.h) Return: 0 if OK, 1 on error Notes: (1) On windows, this will only write tiff and PostScript to memory. For other formats, it requires open_memstream(3). (2) PostScript output is uncompressed, in hex ascii. Most printers support level 2 compression (tiff_g4 for 1 bpp, jpeg for 8 and 32 bpp).
l_int32 pixWriteStream ( FILE *fp, PIX *pix, l_int32 format )
pixWriteStream() Input: stream pix format Return: 0 if OK; 1 on error.
l_int32 pixaWriteFiles ( const char *rootname, PIXA *pixa, l_int32 format )
pixaWriteFiles() Input: rootname pixa format (defined in imageio.h) Return: 0 if OK; 1 on error
Zakariyya Mughal <zmughal@cpan.org>
This software is copyright (c) 2014 by Zakariyya Mughal.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.
To install Image::Leptonica, copy and paste the appropriate command in to your terminal.
cpanm
cpanm Image::Leptonica
CPAN shell
perl -MCPAN -e shell install Image::Leptonica
For more information on module installation, please visit the detailed CPAN module installation guide.