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From "Timo Boehme (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (PDFBOX-4309) Performance regression in PDColorSpace#toRGBImageAWT Part 2
Date Tue, 11 Sep 2018 12:49:00 GMT

    [ https://issues.apache.org/jira/browse/PDFBOX-4309?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16610539#comment-16610539

Timo Boehme commented on PDFBOX-4309:

I tracked the problem more deeply and found that my previous finding was only the tip of the
iceberg (if I skip 'toRGB' trigger it will hang on 'new Color' trigger. The underlying problem
is that if the (ICC) color profile is 'used' (toRGB() or convert-operation) for the first
time it takes about 0.4 seconds (in my environment). Time is spend in native call LCMS.createNativeTransform().

And this call is not only triggered by PDColorSpace.toRGBImageAwt() but also e.g. by ShadingContext.convertToRGB
or PageDrawer.getPaint when drawing a glyph.

Thus the only possibility to prevent these half second delays per ICC profile is my first
proposal to use the alternate color spaces in each case, activated by system property. I will
therefore apply my first patch.

The other solution with drawing selected images 'directly' instead of via ColorConvertOp only
captures part of the problem. It would only be sensible to have this as an alternative to
my first solution if the resulting colors are nearer to the original ones as with the alternative
color spaces and rendering small images is the main problem - depends on document content.

> Performance regression in PDColorSpace#toRGBImageAWT Part 2
> -----------------------------------------------------------
>                 Key: PDFBOX-4309
>                 URL: https://issues.apache.org/jira/browse/PDFBOX-4309
>             Project: PDFBox
>          Issue Type: Improvement
>          Components: Rendering
>    Affects Versions: 2.0.11, 3.0.0 PDFBox
>            Reporter: Timo Boehme
>            Assignee: Timo Boehme
>            Priority: Minor
>              Labels: optimization
>         Attachments: PDColorSpace.java.patch, PDICCBased.java.patch
> This is a continuation of PDFBOX-3569. In a (private) PDF document there are graphics
produced by CorelDraw which are combined by more than 2500(!) images, each with its own indexed
color space based on an ICC color space (the shadows of graphic objects are created by large
number of gray lines ...). In our environment (OpenJDK 7 and OpenJDK 8, IcedTea, Suse Linux
64Bit) rendering a single page with one graphic takes 780 seconds. The most time is spent
in creating the indexed color space via ICC color space mapping:
> {noformat}
>    java.lang.Thread.State: RUNNABLE
>         at sun.java2d.cmm.lcms.LCMS.createNativeTransform(Native Method)
>         at sun.java2d.cmm.lcms.LCMS.createTransform(LCMS.java:156)
>         at sun.java2d.cmm.lcms.LCMSTransform.doTransform(LCMSTransform.java:155)
>         - locked <0x0000000723af9e30> (a sun.java2d.cmm.lcms.LCMSTransform)
>         at sun.java2d.cmm.lcms.LCMSTransform.colorConvert(LCMSTransform.java:268)
>         at java.awt.image.ColorConvertOp.ICCBIFilter(ColorConvertOp.java:355)
>         at java.awt.image.ColorConvertOp.filter(ColorConvertOp.java:282)
>         at org.apache.pdfbox.pdmodel.graphics.color.PDColorSpace.toRGBImageAWT(PDColorSpace.java:314)
>         at org.apache.pdfbox.pdmodel.graphics.color.PDICCBased.toRGBImage(PDICCBased.java:276)
>         at org.apache.pdfbox.pdmodel.graphics.color.PDIndexed.initRgbColorTable(PDIndexed.java:141)
>         at org.apache.pdfbox.pdmodel.graphics.color.PDIndexed.<init>(PDIndexed.java:91)
>         at org.apache.pdfbox.pdmodel.graphics.color.PDColorSpace.create(PDColorSpace.java:184)
>         at org.apache.pdfbox.pdmodel.graphics.color.PDColorSpace.create(PDColorSpace.java:70)
>         at org.apache.pdfbox.pdmodel.graphics.color.PDColorSpace.createFromCOSObject(PDColorSpace.java:240)
>         at org.apache.pdfbox.pdmodel.graphics.color.PDColorSpace.create(PDColorSpace.java:92)
>         at org.apache.pdfbox.pdmodel.graphics.color.PDColorSpace.create(PDColorSpace.java:70)
>         at org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject.getColorSpace(PDImageXObject.java:672)
>         at org.apache.pdfbox.pdmodel.graphics.image.SampledImageReader.getRGBImage(SampledImageReader.java:196)
>         at org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject.getImage(PDImageXObject.java:443)
>         at org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject.getImage(PDImageXObject.java:424)
>         at org.apache.pdfbox.rendering.PageDrawer.drawImage(PageDrawer.java:1046){noformat}
> The call of LittleCMS (LCMS) multi thousand times is the problem here taking way to much
time. Unfortunately using kcms via {{-Dsun.java2d.cmm=sun.java2d.cmm.kcms.KcmsServiceProvider}}
is also no option as the Suse IceadTea OpenJDK seems to not have included it (anymore?) -
in both Java 7 and Java 8.
> However the ICC color space (PDICCBased) returns in this case CMYK as alternate color
space and for CMYK we have the alternative rendering via system property org.apache.pdfbox.rendering.UsePureJavaCMYKConversion
from PDFBOX-3569.
> The idea is now to have an option to force using the alternative color space instead
of the ICC one to circumvent using LCMS in toRGBImage(). For CMYK as alternative color space
it has to be combined with the system property 'UsePureJavaCMYKConversion'.
> Using this approach the rendering time of the page with the problematic graphic drops
from 780 seconds to 1 second!
> It is clear that using the alternate color space might return wrong/not exact colors.
Therefore it should be only an option to enable this mode. However for processing large collections
of PDF documents (e.g. focusing on text) or to display a PDF in a timely manner the performance
improvement should outperform the drop in image quality.
> While the provided patch will use the alternate color space if activated in any case,
it could be possible at a later stage to add more intelligent logic which decides on a runtime
analysis when to use this mode (number of calls to LCMS, time needed etc.).
> If there are no objections with this patch I will apply it in the next days.

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