mupdf - MuPDF PDF reader and library

Age	Commit message (Collapse)	Author
2017-10-25	Fix pgm corruption with spots files.	Robin Watts
	When converting from a source space to a destination space with spots for our "overprint" group push, we were hitting problems in our use of the pixmap converters. Pixmap converters with copy_spots set can assume that the source and destination spots are the same - when copy spots is NOT set, we cannot assume this. This was leading us to have uninitialised group backgrounds. I believe we were only seeing this with pgm because of the device k to cmyk as K only special case. Also fix an error in the fast_gray_to_cmyk routine that failed to account for the change from subtractive to additive.
2017-10-25	Add fz_new_icc_colorspace_from_stream.	Robin Watts

2017-10-24	Add proper handling of bgr<->rgb for pixmap conversions	Michael Vrhel

2017-10-24	Add interface for setting icc space to bgr format	Michael Vrhel
	This is needed so that we can have bgr formatting with something other than the default sRGB
2017-10-24	Handle DeviceBGR <-> DeviceRGB properly	Michael Vrhel

2017-10-24	Don't override non-default Device{Gray,RGB,CMYK} by OI.	Robin Watts
	If the OutputIntent is set, we used to set Device{Gray,RGB,CMYK} (as appopriate) to match it. Don't do this if it's already been set to something other than our defaults.
2017-10-24	mudraw: Add ability to specify icc profile for target colorspace.	Michael Vrhel

2017-10-24	Make a public fz_new_icc_colorspace_from_file function.	Tor Andersson

2017-10-24	Look for changes to Default colorspaces in XObjects.	Robin Watts

2017-10-24	Don't apply default decode array to ICC Lab image data.	Robin Watts
	Adjust the decode array to allow for the fact that the default decode is done by the ICC code.
2017-10-24	Implement DeviceGray to K	Michael Vrhel
	When source color is DeviceGray, and the destination color CMYK we should map the gray values to K. See note in Section 6.3 of PDF spec.
2017-10-24	Change colorspace 'device_n' field to be a flags word.	Robin Watts

2017-10-24	Logic for Sep and DeviceN colorspaces with C,M,Y, or K.	Michael Vrhel
	Special care is required when the DeviceN color space has cyan, magenta, yellow or black. For example, even if we support separations in the destination, if the color space has CMY or K as one of its colorants and we are drawing to an RGB or Gray pixmap we will want to do the tint transform. Also if the pixmap has no seps memember present, we support the separations if the destination is CMYK and the DeviceN colorspace has no "Spot" (non-CMYK) colorants.
2017-10-13	Fix further problem seen in PDF_2.0_FTS/fts_23_2311.pdf	Robin Watts
	This file has a type 3 font in it. It first uses a 'd1' glyph, that uses a pattern. Accordingly, we we render that pattern to a mask tile and store that tile. Then it uses a 'd0' glyph, which uses the same pattern. The cache is checked, and we erroneously pick up the cached tile to reuse it - but this is not a colored rendering, so we assert on plotting. The fix is to ensure that the required colorspaces match. This requires us to add the colorspace to the tile key. Unfortunately, this means that colorspaces have to become key_storable, so the patch is slightly larger than would otherwise be the case.
2017-10-13	Fix assert in fts_23_2311.pdf	Robin Watts
	Ensure that if we ask for a color converter for a NULL colorspace, that we treat it as devicegray. This copes with the mask cases.
2017-10-05	Avoid double literals and double math functions.	Sebastian Rasmussen

2017-09-08	Ensure colorspace colorants are named for ICC spaces too.	Robin Watts

2017-09-08	Update draw device to cope with spots.	Robin Watts
	If draw device is passed a pixmap with disabled separations, it may have to push an extra group at the top to allow for the actual rendering to properly happen in cmyk+spots, and then get folded down at the end. This pushing cannot happen at create time, due to it being dependent on the defualt_cs settings. Accordingly, we push it (just once) on the first drawing operation. This means we need to be able to convert from "colorspace + set of spots" to "different colorspace + different set of spots". This in turn means we need to be able to drive lcms slightly differently (to tell it whether to copy the spots unchanged or not), so we have to amend the CMS interface code a bit for that. Currently we lack plotters to properly cope with plotting images and shades with spots, so this will give a warning and do nothing. To be filled in in future commits. Ensure fz_get_icc_link accepts NULL to mean default color params. Incorporates fixes from Michel Vrhel: With transparency groups we can have RGB + spot pixmaps. When drawing into those we need a mixture of colorant polarity. Ensure that fz_convert_separation_colors takes account of this. Fix C1 of Altona_Technical_1v1_x3.pdf (allow for output intent in fz_clone_pixmap_area_with_different_seps).
2017-09-07	Initialize variables to appease clang scan-build.	Sebastian Rasmussen

2017-08-17	Remove redundant NULL check.	Tor Andersson
	fz_colorspace.name is an array, not a pointer, so will never be NULL.
2017-08-16	Allow access to an indexed colorspace's color entries.	Sebastian Rasmussen

2017-07-19	Add some consts to color conversions.	Robin Watts

2017-07-19	Extend fz_colorspaces to better cope with DeviceN.	Robin Watts
	We now keep a list of colorant names for every colorspace, along with a an 'is_device_n' flag, set for all separation and deviceN spaces.
2017-07-19	Add knowledge of spots to color conversions.	Robin Watts

2017-07-19	Add spots to fz_pixmaps.	Robin Watts
	Update separations interface further to cope with whether spots should be rendered separately, or as composite colors.
2017-07-19	Keep fz_store_hash to declared size.	Robin Watts
	Could shrink this further, but we can't go below another 4 bytes so it's not worth it.
2017-07-17	Fix fz_copy_pixmap_rect to work properly in all cases.	Robin Watts

2017-07-17	Set colorspace name field.	Tor Andersson

2017-07-17	Add colorspace handling to transparency groups	Michael Vrhel
	Also force softmasks to be isolated groups.
2017-07-17	Make sure CMYK ICC color spaces are subtractive	Michael Vrhel

2017-07-06	fz_var() variables must be initialized before fz_try.	Sebastian Rasmussen

2017-07-04	Remove is_static from fz_new{,_icc}_colorspace.	Robin Watts
	No longer required, and causes leaks. Also, fix some reference counting problems with colorspaces.
2017-06-27	Make the entire cached color converter defined in case of error.	Sebastian Rasmussen
	Previously some parts were left undefined which caused problems when finalizing it during the error cleanup.
2017-06-22	Use unsigned char arrays in hexdumped data.	Tor Andersson

2017-06-22	Add Color Management interface to MuPDF, with LCMS implementation.	Michael Vrhel
	This commit adds an interface for a color management engine to MuPDF, together with the internal changes required to use it. We also add an implementation of this interface using the LCMS2 library. This commit is the "lcms" development branch squashed to a single commit. The individual commits that make it up are as follows: ------ Add LCMS2 submodule. Add required source files to MSVC libthirdparty project. Plus changes to the Makefile. ------ Change name of libfont to libresources The library can hold things other than fonts including ICC profiles and eventually halftone screens etc. ------ Generate and include icc profiles on windows solution Makefile for linux needs to be updated ------ Initial cut at interface to little cms Methods for getting profile handles, link handles and transform buffers as well as individual colors. ------ Install ICC profiles from source When the source color space is an ICC profile install the ICC space. Use alternative color space if ICC is invalid. ------ Rename ICC resources The way that fontdump generates the names was causing some redundant prefix/suffix combinations. ------ Make resource ICC profiles usable This brings in the resource profiles for use with the target device. When mudraw is invoked with the icc color type, it will set up the target pixmap to have an icc based color space. ------ Make Default ICC color spaces not storable The ICC color spaces in the color context should not be put into the store. ICC color spaces that are contained in the source document are however storable. ------ Add in support for single color conversion This adds in the selection of the icc single color converter. Note that we may want to look at using the float conversion in lcms here since we are going from and to float. The down side is that the creation of such converters may be expensive. ------ Pixmap ICC conversion Also clean up and further simplify some of the code. Use common dst, src in function parameters instead of src, dst. ------ Add md5 calculation for profiles Compare md5 of source and destination. If they are the same set link as identity and do not bother creating link from cmm. ------ Initial attempt at adding links to store Next need to make sure I have all the dropping set up correctly and that the links are getting freed when we are all done with them. ------ Add drop for link Make sure that we drop the links when we are done with them. ------ Fix icc link store ref. counting + rendering intent The key allocations, rc and removal was wrong for the icc links. Also added in support on the graphic state for rendering intent. ------ Add ICC profiles to Makefile. ------ Move ICC profile loading to colorspace.c ------ Fix build on linux. ------ Use hexdump in creating icc profiles ------ First cut at CalRGB CalGray handling These color spaces are converted to equivalent ICC profiles when the drawing operation occurs. ToDo still is avoid creating brand new CalGray, CalRGB or ICC color spaces when we encounter the same object in the source file. Instead we should make use of the store. ------ Adding fz_color_params into device API Stroke and fill of paths and text which will have color rendering related settings including overprint, overprint mode, rendering intent and black point settings. Images have a fz_color_params member added to them. ------ Rendering intent support for graphic and text Graphic fills and strokes as well as text fill and strokes handle the rendering intent settings. This works through the display list. The parameters related to color rendering, ri, bp, op, opm are packed in the flags bits through the display list. To do: Add support for images and shadings. ------ Add support for rendering intent with images Required change to fill_image api, hence the large number of files touched. ------ Add support for shadings rendering intent and DeviceN This adds support for the rendering intent in shading fills. Also, adds in support for color management of DeviceN and Separation color spaces where the base space is defined to be ICC. ------ Add clamping proc to colorspace-imp.h In the head of mupdf, the index color values were not being clamped properly. I moved the clamping operation to be performed by a procedure in of the color space. The a, b values in LAB will need to include a range value for proper clamping as well as the ICC color space at some point. ------ Fix assert test with index images ------ Support for DeviceN images color managed The base space for DeviceN and separation images is now color managed when the ICC work flow is used. ------ Add DefaultGray etc to names.txt The DefaultGray, DefaultRGB, and DefaultCMYK settings in the pdf page resource dictionary need to be parsed and handled if present. ------ Remove methods for setting color space in context The methods that existed for setting the color spaces in the color space context were broken and we will not be changing them from their initial setting at startup. ------ Add front end support for default color spaces PDF can specify in the resource dictionary color spaces that should be used for DeviceGray, DeviceRGB and DeviceCMYK. This commit handles the extraction of these color spaces and passes them through the display list and gets them into a structure on a draw device (if one is used). Next step is to have the draw device make use of them. ------ Backend of default color spaces This handles the use of page level definitions for DefaultGray, DefaultRGB, DefaultCMYK in the draw device. The interface for the pixmap color conversion had to be expanded a bit to pass the default_cs object. This was needed due to the fact that the image could be DeviceN or Separation and have a base space that needs to be replaced by a page level Default color space. Tested this with a file that had two pages each with an common reference image object but different DefaultCMYK definitions in the page resource dictionary. Proper rendering was obtained. ------ Add icc support to band-writer and png output For image viewers that support icc profiles, it is important that we include the icc profile into those formats that support. Currently the only output format we have that supports it is PNG. But if we decide to do tiff, jpeg or psd those also support the embedding of icc profiles. ------ Work toward multithreading Each cloned context creates a new cmm context to reduce contention. This may not be optimal though as it may create conflicts in any shared store. ------ Add missing files. Failed to check in icc-imp.h and icc34.h ------ Fix default device color calls copy and paste errors. ------ Fixes ------ Fix clamping of lab colors The lab colors when used with the lab resource profile need to be properly clamped and scaled. ------ Turn off ICC create debug define ------ Fix memory leak issues ------ Set clamp proc in color context color spaces When NO_ICC is enabled there was an issue as the default spaces did not have the clamp proc (which was added in the lcms branch). ------ Fix several issues after rebase During rebase of the branch there were several issues that came up. In addition there was a fix related to the use of the lcms2 context branch that did not make it in for some reason. ------ Fix for fz_store_type structure changes ------ Fixes for multithreaded This fixes a few issues. One issue is that we can not be changing the input and output formatter for the links if they are being shared among threads. This adds the format as part of the link definition. Next step is to create a link clone operation in lcms so that we can readily create a different one with everything the same except the formatter. Also, this shares the profiles that exist in the color context among the threads. When a context is cloned, it will use the profiles in the current context but it will create a new cmm context.c ------ Fix NO_ICC issues There were a few issues that occurred when we compiled and ran with the NO_ICC setting. ------ Change CMM to use lower resolution tables in links The table resolution greatly affects the performance for some files. I don't see any significant color rendering issues going with a lower resolution. Selecting cmsFLAGS_LOWRESPRECALC uses a MLUT resolution of 17. This is going to be sufficient color wise and gives a large improvement performance wise especially for files where the color link creation is significant compared to the rendering. ------ Fix link key creation to populate alpha and bit depth. The store key for icc links needs to include the bit depth and if the transform has to handle an alpha value. This is needed due to the fact that we can't change the formatter when we are sharing links among different threads. ------ Pull in some MSVC 2005 fixes for lcms2 ------ Fix non-prototype prototype. ------ Miscellaneous typos, whitespace fixes. ------ Tidy colorspace creation API. Rather than pass a magic implementation reference count value (-1 for static, 1 for normal), pass a boolean "is_static" flag. This gives a nicer API (IMAO etc). ------ Make all colorspaces use an fz_buffer. ------ Fix internal naming of MSVC project file. ------ Fix some error handling. ------ Add some consts. ------ Tweak fz_color_params and fz_store_hash. Use uint8_t for fz_color_param entries - no need to use larger. Same change in fz_store_hash. This limits the size required for the hash table too. ------ Throw on errors, rather than returning NULL. fz_cmm_transform_pixmap should throw if it's fed pixmaps incompatible with its transforms. fz_cmm_new_ctx should throw if the cmm fails to initialise. ------ Ensure LCMS2_OBJs are built/linked using Makefile. Also ensure that ICC_OBJs are included. ------ Fix some unused variable warnings. ------ cs_params fixes. Use the ones that are passed. ------ fz_color_params tweaks. Make them const in many places. Cope with cs_params == NULL meaning default (i.e. fz_cs_param(ctx)). Minimise the places we call fz_cs_params(ctx). Consistently use cs_params rather than a mix of cs_param and cs_params. ------ Improve PDF color params handling. PDF allows different OP settings for strokes and fills. This means that either we need to keep separate entries in each fz_color_param structure for the stroke one or the fill one, OR we need to duplicate the fz_color_param structure. It seems neatest to do the latter (not least because this means we don't pass more information to each device function than it actually needs). Accordingly, we put an fz_color_param in each pdf_material. We update the code that reads ExtGStates to set the values appropriately. We take the opportunity to add support for the PDF 2.0 UseBlackPtComp option too. ------ Fix colorspace ref count problems. 1) Don't drop colorspace until we've finished using it. 2) Don't drop it twice. ------ Convert NULL deref into a thrown error. Seen with: mutool draw -D -o out.png ../tests_private/comparefiles/Bug689760.pdf We seem to have a pdf-cal space with no profile. Talk to Michael about this. ------ Avoid using colorspace names to distinguish colorspaces. Using strcmp is slow. ------ Cope with failure to parse default colorspaces during PDF page load. ------ Avoid SEGV due to to pdf_cal space with no profile. As seen in: tests_private/pdf/PDFIA1.7_SUBSET/CATX4879.pdf ------ Handle cases where base space of sep is pdf-cal We handled this for images, but not for solid fills. ------ Accelerate ICC color conversion. ------ Cope with indexed images in the color management. Some images (JPX images) come to the cm code still in the indexed color space. Their base space could be DevN so we need to cope with multiple base decodes. This continues the decode until we get to a space for which we can create an ICC link. ------ Ignore alpha presence in component count check ------ Eliminate recursion in fz_source_colorspace_cm. ------ Cope with bare ICCBased colorspace defs. Bug692137.pdf has ICCBased colorspaced definitions given directly as a stream, rather than as [ /ICCBased <stream reference> ] Acrobat copes with these, as does gs. We therefore update our code to cope too. Also, the PDF spec says that any problems found when reading the Default spaces should be ignored (or at least not to abort rendering). Update our code to do that too. ------ Tweak color converter logic for speed. When we are using an icc profile based conversion, avoid ever having to lookup the color converter for each conversion call; do it at the lookup stage. ------ Harden us against failures during ICC link creation. Seen with corrupted profiles. ------ Fix for handling alpha with lcms. Note that this currently maintains an alpha when it is present. We may need to do some work for the gray scale conversion to alpha mask. ------ Delay pdf-cal profile creation Put the creation of the pdf cal profile into the link creation function (rather than have it scattered). Also be robust in the condition of failure to create the profile. ------ Proper clamping with embedded CIELAB ICC profile If the ICC profiles alternate color space is LAB then use the LAB clamping proc. ------ Use the color space clamp when converting to base color spaces In many of the Ghent test files, we have a DeviceN image whose alternate color space is CIELAB. We need to make sure to use the CIELAB clamping operation in this case. ------ Make ICC runtime configurable. Add fz_icc_flowflow, fz_set_icc_workflow functions to read ICC workflow state, and set the ICC workflow state. The latter will throw an error if trying to enable ICC workflow in a NO_ICC build. Add -N flag to mutool to disable ICC. Incorporates build fixes from Michael. ------ Ensure fz_draw_fill_image uses the pixmap colorspace It appears that the image colorspace historically has been able to differ from the pixmap colorspace. While we've fixed the cases that we know about for this (see the previous commits), tweak fz_draw_fill_image to work the way it always has in the past. ------ Add support for output intent PDF documents can have an ICC profile defined in their Catalog which defines the output color space and the color space to use for one of the Device color spaces (e.g. DeviceGray, DeviceRGB or DeviceCMYK). ------ Catch errors in default color spaces Before setting the default color space contained in the file, make sure it is the correct type. Bug692213.pdf ------ Clamp to base space during sep color conversion This was the source of a problem when the base space was CIELAB. ------ Rename some functions to be more MuPDFy drop rather than free etc. ------ Fix "casting away const" warning. srcv is a const *. Do the clamping operation on src_map (the same value) before it is assigned into the const variable. ------ Rejig top level color management interface slightly. Same code, just change the encapsulation. ------ Remove pre-multiplied alpha prior to color management The pixmaps in mupdf use a premultiplied alpha format. Prior to doing any color management we need to undo the alpha and then reapply after color management. ------ Remove global output intent as unused. ------ Move fz_color_params to be the final arg in dev calls. Frequently this will be NULL, and it doesn't form part of the colorspace/color/alpha triple. ------ Rename fz_default_xxx static variables. Remove fz prefix, to prepare for a later renaming that would conflict. ------ Rename cs_params to color_params. ------ Rename lcms branch identifiers. ------ Return device colorspaces if the default colorspace is NULL. ------ Clean up device call function for set_default_colorspaces. ------ Add missing rethrow. ------ Load page default colorspaces lazily. ------ murun: Add color params device argument. Stubbed to always be NULL at the moment. ------ Rename extgstate processor ops. ------ Fix a few minor issues from Tor Removes icc-imp.h Rename color-icccreate.c Add context to some methods ------ Fix javalib with recent lcms dev changes. ------ Update lcms2 with sub project fixes. ------ Fix build failure. ------ Add icc profile into other PNG output methods ------ Fix some ints that should be size_t's. ------ Tweak fz_new_icc_data_from_icc_colorspace. Ensure that the colorspace is const, and that we set size to 0 if we don't find any data. ------ Combine band writer methods for header and ICC writing For many formats (like PSD), we need to delay writing some of the header until we know whether we are getting an ICC profile to write or not. Makes more sense to just write them at the same time. ------ Miscellaneous tweaks in colorspace.c Mainly to avoid pointer aliasing, "nicer" whitespace, and a leak on error. ------ Avoid rightward drift in get_base_icc. ------ Ensure that pdf_load_output_intent copes with exceptions. If load_icc_based throws and exception, warn and continue. Don't not render a file just because the inbuilt default profiles are broken. ------ Revert change in pdf-page.c The page resources load had been moved so we could get the default colorspaces, but this has been moved into run_contents, so putting stuff back as it was before. ------ Revert changes in mudraw. We had added some colorspages in mudraw, and then later removed them. Revert the changes to accomodate this to make the overall branch diffs smaller. ------ Use fz_buffer in color-icc-create.c ------ Force mapping through proof icc profile always. ------ Fix behaviour on fz_cmm_new_profile failure. If the profile fails to be made, return an error code, and have the callers take sane steps. ------ Tweak load_icc_based Cope better with errors in reading the ICC space not stopping us loading the alternate. ------ Remove unused variable. ------ Get page resource for DefaultCS look-up res = pdf_dict_get(ctx, PDF_NAME_Resources, page->obj); was not returning resource. Replaced with res = pdf_page_resources(ctx, page); ------ Move default color space set up to pdf_run_page_contents_with_usage ------ Review fixes for lcms branch. ------ Fixes for calibrated colorspace loading. ------ Add fz_document_output_intent wrapper. Lazy load intent for PDF. ------ Copy DefaultCS logic into pdf_run_annot_with_usage. Same code as from pdf_run_page_contents_with_usage. ------ More review fixes. ------ Avoid rightward drift in pdf_load_cal_common ------ Rename color_converter functions to be find/drop. Better than than lookup/discard. lookup suggests something that doesn't need dropping, and we use drop rather than discard by convention. ------ Move cmm from context into colorspace context. ------ Review fixes: Remove recursion and rename functions. ------ Don't access doc->oi directly in pdf_load_default_colorspaces. ------ Rename fz_colorspace_is_pdf_cal to fz_colorspace_is_cal and make it public. ------ Tweak function naming to be more consistent. ------ fz_md5_icc can be implemented using fz_md5_buffer. ------ Print full md5 checksums in link key debug prints. ------ Make fz_md5_buffer NULL safe. ------ Simplify debug saving of ICC profiles. ------ Rename fz_cmm_new/drop_profile to init/fin. ------ Indentation cleanups. ------ Move CMM static inline functions from private header to C file. ------ Tweak fz_icc_data_from_icc_colorspace to return a buffer. Also, remove the _new_ from the name to reflect the fact that we are passed a borrowed handle, not given a new reference. ------ java: Add ColorParams.pack() function. ------ Generate one C file for the embedded ICC profiles. ------ Return const pointer from fz_default_color_params. ------ Change misleading argument names to fz_new_colorspace. ------ Rename fz_cmm_new/drop_link to fz_cmm_init/fin_link. ------ Change definition of fz_cmm_instance. Rather than void, use an undefined struct in keeping with the rest of the code. ------ Add support for color managed bgr color space ------ Return unsigned char array from fz_lookup_icc. ------ Make default_color_params immutable. Changing the defaults used by the draw device should happen via a device call, should we need the functionality in the future. ------ Clean up error handling in color-lcms.c ------ Fix signed/unsigned warning.
2017-05-31	Avoid double literals causing casts to float.	Sebastian Rasmussen

2017-04-27	Include required system headers.	Tor Andersson

2017-01-17	Add value destructor callback to fz_hash_table.	Tor Andersson
	This allows us to prune the iteration functions. We also remove a few other unused functions.
2016-12-27	Strip extraneous blank lines.	Tor Andersson

2016-12-27	Common code to ensure we only premultiply pixmaps with additive colors.	Tor Andersson

2016-12-14	Let pixmap colorspace conversion create new pixmap.	Sebastian Rasmussen
	This moves dropping the converted pixmap into fz_convert_pixmap(), which relieves every caller from doing so. Moreover resolution, position and interpolation are kept.
2016-12-14	Create a pixmap color converter.	Sebastian Rasmussen
	This is in preparation for moving fz_convert_pixmap() out of colorspace.c.
2016-10-19	Rename internal headers to follow pattern *-imp.h.	Sebastian Rasmussen

2016-10-18	Avoid checking argument to fz_drop_*()/fz_free().	Sebastian Rasmussen
	As fz_drop_*()/fz_free() all must handle NULL.
2016-10-14	Drop all contexts the same way.	Sebastian Rasmussen
	* Handle multiple calls to fz_drop_colorspace_context() and fz_drop_font_context(). * Allow missing context in call to fz_drop_aa_context() and fz_drop_glyph_cache_context(). * Only drop font context objects when dropping the last reference. * Avoid unnecessary NULL checks.
2016-10-12	Bug 697065: Fix bug in CMYK -> RGB pixmap converter.	Robin Watts
	When caching the cmyk values used to generate a given rgb value, it is best to cache the values before processing.
2016-10-06	Hide internals of fz_colorspace	Robin Watts
	The implementation does not need to be in the public API.
2016-07-06	Expose LAB colorspace	Sebastian Rasmussen

2016-06-17	Use 'size_t' instead of int as appropriate.	Robin Watts
	This silences the many warnings we get when building for x64 in windows. This does not address any of the warnings we get in thirdparty libraries - in particular harfbuzz. These look (at a quick glance) harmless though.
2016-06-06	Bug 696810: Avoid integer overflows.	Robin Watts
	When blanking pixmaps (or converting pixmap colors), watch out for integer overflows.