Bug 39733

Summary:

Printing code should break a page only at allowed page breake positions

Product:

WebKit

Reporter:

Hayato Ito <hayato>

Component:

Printing

Assignee:

Nobody <webkit-unassigned>

Status:

UNCONFIRMED

Severity:

Normal

CC:

hamaji, hyatt, m.kurz+webkitbugs, norman.jonas, schenney, t.bussmann, webkit.review.bot, yuzo

Priority:

Version:

528+ (Nightly build)

Hardware:

OS:

OS X 10.5

Bug Depends on:

Bug Blocks:

39735

Attachments:

Description	Flags
A patch for Bug 39733	none
Patch for Bug 39733, 2nd attempt	none

Hayato Ito

Reported 2010-05-26 07:20:16 PDT

For example, suppose the height of page is 1000px and try to print the following html. <html> <body> <div id="block1" style="height:800px;border:1px solid red"></div> <div id="block2" style="height:800px;border:1px solid green"></div> </body> </html> According to CSS3's Paged Media specification (see bellow), a page break should occur between 'block1' and 'block2'. The current printing code breaks a page inside 'block2'. Breaking a page at disallowed position should be a last resort. - Opera 10.5.3 (Mac OS X 10.5) breaks a page between 'block1' and 'block2' correctly. - Firefox 3.6.2 (Mac OS X 10.5) has the same behaviour as WebKit. CSS3 PagedMedia 9.4. Allowed page breaks and Rule A, B, C and D. http://dev.w3.org/csswg/css3-page/#allowed-pg-brk

Attachments
A patch for Bug 39733 (8.64 KB, patch) 2011-06-01 15:40 PDT, Stephen Chenney	no flags	Details Formatted Diff Diff
Patch for Bug 39733, 2nd attempt (8.75 KB, patch) 2011-06-01 15:48 PDT, Stephen Chenney	no flags	Details Formatted Diff Diff
Show Obsolete (2) View All Add attachment proposed patch, testcase, etc.

Stephen Chenney

Comment 1 2011-05-31 14:20:10 PDT

I have a fix for this under local testing.

Stephen Chenney

Comment 2 2011-05-31 14:23:48 PDT

Note that this bug is tested via the following layout tests: printing/allowed-page-breaks-expected printing/page-break-after-avoid printing/page-break-before-avoid printing/page-count-percentage-height These tests are currently expected to fail, in part due to this bug. Except page-count-percentage-height which I think has incorrect expected results right now.

Stephen Chenney

Comment 3 2011-06-01 15:40:55 PDT

Created attachment 95677 [details] A patch for Bug 39733 The patch modifies the code that determines if a block may be split across a page when paginating (but not paginating for columns). The test now considers blocks with zero or 1 child as unsplittable. Some existing tests that were FAIL are now PASS.

WebKit Review Bot

Comment 4 2011-06-01 15:43:45 PDT

Attachment 95677 [details] did not pass style-queue: Failed to run "['Tools/Scripts/check-webkit-style', '--diff-files', u'LayoutTests/ChangeLog', u'LayoutTests/prin..." exit_code: 1 LayoutTests/ChangeLog:6: Line contains tab character. [whitespace/tab] [5] LayoutTests/ChangeLog:7: Line contains tab character. [whitespace/tab] [5] LayoutTests/ChangeLog:11: Line contains tab character. [whitespace/tab] [5] LayoutTests/ChangeLog:13: Line contains tab character. [whitespace/tab] [5] LayoutTests/ChangeLog:15: Line contains tab character. [whitespace/tab] [5] LayoutTests/ChangeLog:17: Line contains tab character. [whitespace/tab] [5] LayoutTests/ChangeLog:18: Line contains tab character. [whitespace/tab] [5] LayoutTests/ChangeLog:19: Line contains tab character. [whitespace/tab] [5] LayoutTests/ChangeLog:20: Line contains tab character. [whitespace/tab] [5] LayoutTests/ChangeLog:22: Line contains tab character. [whitespace/tab] [5] Source/WebCore/ChangeLog:6: Line contains tab character. [whitespace/tab] [5] Source/WebCore/ChangeLog:7: Line contains tab character. [whitespace/tab] [5] Source/WebCore/ChangeLog:8: Line contains tab character. [whitespace/tab] [5] Source/WebCore/ChangeLog:12: Line contains tab character. [whitespace/tab] [5] Source/WebCore/ChangeLog:14: Line contains tab character. [whitespace/tab] [5] Source/WebCore/ChangeLog:15: Line contains tab character. [whitespace/tab] [5] Source/WebCore/ChangeLog:16: Line contains tab character. [whitespace/tab] [5] Source/WebCore/ChangeLog:18: Line contains tab character. [whitespace/tab] [5] Total errors found: 18 in 9 files If any of these errors are false positives, please file a bug against check-webkit-style.

Stephen Chenney

Comment 5 2011-06-01 15:48:00 PDT

Created attachment 95678 [details] Patch for Bug 39733, 2nd attempt Removing tabs from ChangeLog files.

Stephen Chenney

Comment 6 2011-06-07 15:06:07 PDT

Comment on attachment 95678 [details] Patch for Bug 39733, 2nd attempt I'm withdrawing this, as I am not confident it will work in cases where there is a divisible item within the block.

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