NAME
Image::Leptonica::Func::writefile
VERSION
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)FUNCTIONS
getFormatExtension
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.getImpliedFileFormat
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.pixChooseOutputFormat
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.pixDisplay
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.pixDisplayMultiple
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.pixDisplayWithTitle
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.pixDisplayWrite
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.pixDisplayWriteFormat
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 bytepixSaveTiled
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.pixSaveTiledOutline
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.pixSaveTiledWithText
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.pixWrite
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.pixWriteImpliedFormat
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.pixWriteMem
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).pixWriteStream
l_int32 pixWriteStream ( FILE *fp, PIX *pix, l_int32 format )
pixWriteStream()
Input: stream
pix
format
Return: 0 if OK; 1 on error.pixaWriteFiles
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 errorAUTHOR
Zakariyya Mughal <zmughal@cpan.org>
COPYRIGHT AND LICENSE
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.