Mako 6.2.0 Release Notes

MAKO-2960

Vector-based transparency flattener

This release sees the introduction of a new method to flatten transparency that traces shapes with vector paths rather than rasterising them, avoiding the jagged edges that result.

New APIs are added to the IRendererTransform interface:

setEnableVectorMode(bool enable)

• Pass true to enable the feature

setVectorAndTextResolution(uint32 resolution)

• Sets the desired resolution for vector and textual content when vector flattening mode is enabled. The default is 1200dpi.

setRasterFallbackThreshold(uint32 threshold)

• Sets the threshold at which to fall back to raster mode for a particular renderable area. The threshold is specified in terms of rendered objects per square inch. If a rendererable area would result in more generated objects than this threshold, the renderer will fall back to a pure raster. The default value is 100.

Example of vector-based flattening

In this example, two partially transparent shapes overlap, and set to use a multiply blend.

Zooming in to the top of the area of intersection:

The result of regular raster-based flattening. The shapes are rasterized (at somewhat low resolution for the purposes of illustration) and you can see the jagged edges that result.

The result of vector-based flattening. The edges are smooth.

This image shows how the vector flattener has created three new vector paths that no longer overlap (moved apart for the purposes of illustration), with the color of 2 representing the blend evident in the original artwork.

MAKO-3311

Enable /CompressObjects with an additional IDistiller() API

An additional API is added to the IDistiller class to support compressing of individual objects by internally setting the CompressObjects distillerparam. Applies to PDF 1.5 and later.

Use IDistiller::setCompressObjects(true) to enable. The default value is false.

Documentation for the SDK samples MakoDistiller and MakoDistillerCmd have been updated accordingly.

MAKO-3320

Add equivalent of PDFLib's SetPageFilterRange to IDistiller

Three new API functions are added to IDistiller to specify which pages in a PostScript job are processed.

• setPageFilterLow() sets a lower page limit

• setPageFilterHigh() sets an upper page limit

• setPageFilterRange() sets a range of pages to output

Use it in this way. (This code is C++; this API is also available in C# & JAVA).

const auto mako = IJawsMako::create();
IJawsMako::enableAllFeatures(mako);
auto distiller = IDistiller::create(mako);

// High & Low
distiller->setPageFilterLow(10);
distiller->setPageFilterHigh(20);
distiller->distill(
    IInputStream::createFromFile(mako, "test100.ps"),
    IOutputStream::createToFile(mako, "test10-20.pdf")
);

// Range
distiller->setPageFilterRange(10, 20);
distiller->distill(
    IInputStream::createFromFile(mako, "test100.ps"),
    IOutputStream::createToFile(mako, "rangeTest10-20.pdf")
);

Additionally, setParameter() is also available to set the lower and upper limits. This API expects values as strings, useful for command-line apps etc., e.g.

 // Or use setParameter
distiller->setParameter("PageFilterLow", "10");
distiller->setParameter("PageFilterHigh", "20");

• Page numbers are expressed as actual page numbers, in line with the Jaws PDFLib API that this replaces. This contrasts with most Mako APIs that use a zero-based numbering scheme.

• This feature does not implement the JAWS PDFLib API SetPageFilterCallback().

MAKO-3350

IJPDS Performance improvement

In response to customer requests, the IJPDS input class has undergone significant refactoring that has resulted in an average performance increase of 71%. In particular, the method for obtaining the number of pages now returns almost immediately for most jobs.

MAKO-335X

IJPDS input class: additional options to control assembly of output pages

The method to instantiate the class remains the same, but the available parameters have changed.

IIJPDSInputPtr input = IIJPDS::create(jawsMako);
input->setParameter("ripsetup", "cmyk");

This is a complete list of the available parameters. Items marked with an asterisk are new in this version.

MAKO-3275

Add support for PDF 1.5 output

This corrects the omission of PDF 1.5 from the list of supported PDF versions to choose from when using IPDFOutput::setVersion(). See this documentation for details.

MAKO-3433

Support CMYK encoding of JPEG

Until this version, saving a Mako IDOMImage or IImageFrame to JPEG meant converting to RGB first. This change adds two additional parameters that permit the encoder to write CMYK data (if available) and whether it should be inverted beforehand. The parameters are:

MAKO-3249

Push setFunction() down into IDOMShadingPatternBrush

This change was requested by a developer in Global Graphics’ Technical Services team.           

The setFunction() abstract declaration has been moved into IDOMShadingPatternBrush rather than the derived classes, all which use the function.  For consistency the same has been done with getFunction().

MAKO-3307

Create VS2017 build of Mako 6.2.0

Responding to customer demand, the VS2017 build makes a comeback in this release. x64 only.

MAKO-3314

MAKOSUP-10650 Critical MAKO render performance

The exhibit PDF was very slow to render, taking hours instead of the expected minutes. This job is extremely punishing, consisting of a lot of gradients, particularly radials, with plenty of transparency and overlapping objects. Improving performance for this use case required identifying where the fastest code path for a given process was not being taken, then making the necessary changes to enable those to be used. Additionally, several smaller performance gains, taken together, added to the overall performance improvement.

An anti-aliasing setting of 4 requires a rendering resolution of 900dpi (9 × the data)

MAKO-3362

MAKOSUP-10697 Text incorrectly hidden by redaction

While applying redaction to text that happened to be on a non-white background, Mako was losing track of the z-order of objects with the result that adjacent text, not part of the redacted area, was being obscured by the background. This is now fixed.

In addition, a new parameter is added to the redactor transform:

IRedactorTransform::setGenerateMasks(bool generateMasks)

Sets whether masks should be generated when rendering redacted sections. The default is true. Setting this false will result in the text becoming part of the rendered image which may be preferred. The text remains in the DOM, so can still be selected, and searched for.

MAKO-3291

MAKOSUP-10699 Memory usage grows to 10GB then segfaults

The exhibit contains a very large clip, most probably the result of an error in the generator of the PDF. It caused scan-conversion at PDF input time to trigger an overflow. There is a straightforward workaround providing such a case is detected, and this is implemented in Mako 6.2.0. With it, the exhibit processes normally and memory usage remains below 30MB.

MAKO-3295

MAKOSUP-10700 Arabic ligature problem

The customer’s use case is that they wish to use IDOMGlyphs::getFlattenedGlyphInfo() and see the Arabic ligature in the Unicode information that it returns. Prior to this change, the IDOMGlyph::Data unicodeID would only be populated in this situation if the Unicode was a single code point. Following this change, the IDOMGlyph::Data unicode member now contains the sequence of Unicode codepoints for the ligature, in the form of a UTF32 string, giving the customer what they need.

MAKO-3304

MAKOSUP-10701 An expected PDF object was not found Error

This problem surfaced when combining two PDFs. The issue is triggered by several annotations sharing the same AP (appearance) dictionary, which for various reasons was not handled correctly. Now fixed.

MAKO-3310

MAKOSUP-10703 Add the ability for Optional Content to be updated while an IOutputWriter is in progress

This change adds a new API - IPDFOutput::setAllowOptionalContentUpdateDuringWrite() (and a corresponding parameter “AllowOptionalContentUpdateDuringWrite”) that will allow Optional Content to be updated while an IOutputWriter is in progress.

For this to work, groups being used on a given page must have been added to the optional content before writing that page. Note also:

• Deleting groups is not advisable

• Editing groups will not reliably result in the edits being honored - it’s undefined behavior and should be avoided

The API documentation includes these details and more. Enter setAllowOptionalContentUpdateDuringWrite into the Search box

MAKO-3309

MAKOSUP-10706 Support Type 4 (PostScript Calculator) functions for Shading Patterns

The exhibit had some unusual shading patterns, in particular a Type 4 pattern in a shade that Mako was unable to handle, eventually causing a segmentation fault during processing.

The fix adds full support for Type 4 functions in patterns.

MAKO-3346

MAKOSUP-10712 IFormUnpackerTransform crashes

The solution required a workaround for a broken PDF.  The exhibit PDF defined a form with a BDC operator for marked content but did not end it with EMC. Mako will now tolerate such a discrepancy.

MAKO-3345

MAKOSUP-10715 Disappearing glyphs

This issue was triggered by an unusual font cmap encountered in the exhibit PDF. A fix to Mako’s Format 4 cmap subtable decoding was required.

MAKO-3452

MAKOSUP-10719 PDF to PDF conversion error

The exhibit contained a badly formed ICC profile, and this was reported back to the customer. Mako has some protections for bad ICC profiles, but for the exhibit, the problem was the stream itself. Rather than report an error, Mako now falls back to the alternate space, or a device space if no alternate is provided, allowing the job to complete normally.

MAKO-3374

MAKOSUP-10720 File does not succeed in Render

This issue was fixed by the work for MAKOSUP-10706: Support Type 4 (PostScript Calculator) functions for Shading Patterns.

MAKO-3371

MAKOSUP-10732 Error Code 2300, error opening input PDF stream

The solution required a workaround for a broken PDF.  The exhibit PDF defined a /Info dictionary with a /Title string that had a unescaped '(' in the middle of the string. Mako will now tolerate such an occurrence but is not able to recover the document properties.

MAKO-3382

MAKOSUP-10733 Thumbnail SIGSEGV

When rendering the exhibit PDF at low resolution, a segmentation fault is thrown. Now fixed.

MAKO-3420

MAKOSUP-10736 SIGKILL / High memory issue

The combination of Metadata streams in excess of 8 megabytes present in the exhibit, plus an error in code concerned with allocating memory, caused Mako to throw an out-of-memory exception. A simple fix solved the problem and keeps memory consumption below 2GB.

MAKO-3425

MAKOSUP-10749 Exception while loading specific pdf

Pre-flight checks warn of font and syntax errors that the exhibit presents with, and Mako failed with a CID font substitution error. A solution was found. Now fixed.

MAKO-1942

Mako signals undefined error for 12_14K.PS

An obscure error when rendering Type 1 Shading Patterns is now fixed.

MAKO-2450

Character stroke overprinting not being retained

The exhibit features white text on a colored background, with a black stroke which was not overprinting correctly. Now fixed.

MAKO-2454

Backgrounds of graphs wrong when converting PDF to PDF

The exhibit features graphs that lost color information during processing. Now fixed.

MAKO-2568

CMAP test fails when processing 409-01.PS with makodistiller

The exhibit features specific PostScript tests, one of which is designed to test a CMap (PostScript Level 3 Character code mapping). It now passes.

MAKO-3250

Investigate why imposition output is larger in 6.1.0 than 6.0.1

Processing to produce large imposition signatures produced PDFs whose size unexpectedly grew in Mako 6.1.0. Investigation showed this was due to an improvement made to retain XMP metadata associated with images that interfered with the hashing mechanism thereof, reducing the opportunity to cache repeated images. This has now been addressed, and further improved by also enabling caching of XMP packets, bringing file sizes back down to below those seen in Mako 6.0.1.

MAKO-3256 … MAKO-3261

MAKO-3298
…MAKO-3301

Memory leak issues

As part of an ongoing effort to track down and fix memory leak issues, these stories were completed during the Mako 6.2.0 development cycle.

MAKO-3283

Transparency blending is not processed correctly with alphaGeneration feature

Mako 6.1.0 introduced a new option generate an alpha channel when rendering page content. During testing an example was found where this option interfered with regular transparency blending. Now fixed.

MAKO-3284

Issue triggered by recent clipping changes

Mako 6.1.0 introduced improvements to object clipping behavior but these were later found to have some undesirable, albeit minor, side effects. Now addressed.

MAKO-3287

Fonts in MakoDistillerCMD output differ from PDFLib and Acrobat Distiller

It was noted during testing that the different PostScript to PDF conversion routes were producing different output, even though the same underlying code was in use in all three. This led to some lengthy investigation and subsequent refactoring of font handling logic to eliminate discrepancies and produce correct output from the IDistiller class.

MAKO-3319

Ensure that complex gstate parameters are applied for stroked char path groups

This was discovered when comparing rendered output from before and after PDF-to-PDF processing by Mako. Although the visual improvements are very small (typically a few pixels difference), our aim for Mako is zero visual differences between an input and an output PDF, where no deliberate changes are made.

MAKO-3323

PDF Output: Incorrect UCR function written for PostScript Calculators with a Domain

Found during routine testing. Now fixed.

MAKO-3324

Fix LAB color space range handling for PDF output

Found during routine testing. In some circumstances Mako was not emitting the correct LAB Range entries from the source space. Now fixed.

MAKO-3325

Correct a UserUnit pattern matrix issue causing patterns to be incorrectly placed

Found during routine testing. Incorrect scaling of an element occurred due to the UserUnit scaling value not being correctly considered. Now fixed.

MAKO-3327

Implement Type 3 render mode semantics for PDF 2.0

Found during routine testing. Two jobs were not rendering as they should. Further examination showed rendering modes not being honoured for text using Type 3 fonts. However, both were PDF 2.0, the specification for which updates text rendering mode requirements. Once the necessary changes were made, the jobs rendered correctly.

MAKO-3336

PDF front-end truncating CID font widths information

When converted PDF-to-PDF with Mako, the job exhibited shifts in glyph position when the input and output were compared. One solution for this is to round rather than truncate the values in question, but the one adopted was simpler and more accurate: switch to using floating-point values rather than integers.

MAKO-3337

Default color spaces not being applied to inline images

Found during routine testing. Following PDF-to-PDF processing, inline images on a page exhibited a color shift. The fix required refactoring of core code to deal with default color spaces, ensuring special color spaces (e.g., Indexed, Separation, DeviceN and Pattern) which can have an underlying device space are handled correctly.

MAKO-3339

Characters appearing where notdefs should be for PDF to PDF

Found during routine testing. The exhibit was unusual as it used a font type that did not specify an encoding, and the encoding to which Mako defaulted was the wrong choice, leading to a character that should have displayed as a notdef, instead displayed as a glyph. Now fixed.

MAKO-3367

Improve text knockout handling

Found during routine testing of a PDF 2.0 test suite designed to exercise these document features. When converting PDF-to-PDF, text was not knocked out correctly. Now fixed.

MAKO-3380

Fix an issue triggered by the fix of MAKO-3304 (IA2_2106.PDF)

Found during routine testing. The change for MAKO-3304 caused this job to crash. The job is bad: one of the Form XObjects used as an annotation appearance is a dictionary and not a stream(!) This is not allowed, but Mako didn’t cope with the breakage. Now fixed.

MAKO-3388

Rendering some jobs to CMYK results in disappearing text

Found during routine testing. A problem caused by incomplete detection of opaque text resulted in text being dropped from rendered output. Now fixed.

MAKO-3389

Floating point CFF parameters rounded by Jaws

Found during routine testing of PDF-to-PDF conversion. Fonts of the CFF (Compact Font Format) variety were not retaining their scaling parameters correctly, leading to small variations in height and width. Now fixed.

MAKO-3407

Patterns applied to Type 3 text not scaled correctly

Now fixed.

MAKO-3431

Correctly clip and scale ICC LAB colour values in Mako PDF input

For ICC colour spaces, Mako was simply clamping all input values to the range 0 to 1. For LAB profiles however, the PDF specification specifies L 0<->100, A -128<->127 and B -128<->127. Now fixed.