From 5f8de423f190bbb79a62f804151bc24824fa32d8 Mon Sep 17 00:00:00 2001 From: "Matt A. Tobin" Date: Fri, 2 Feb 2018 04:16:08 -0500 Subject: Add m-esr52 at 52.6.0 --- layout/doc/frame_reflow_debug.html | 224 +++++++++++++++++++++++++++++++++++++ 1 file changed, 224 insertions(+) create mode 100644 layout/doc/frame_reflow_debug.html (limited to 'layout/doc/frame_reflow_debug.html') diff --git a/layout/doc/frame_reflow_debug.html b/layout/doc/frame_reflow_debug.html new file mode 100644 index 000000000..e85672650 --- /dev/null +++ b/layout/doc/frame_reflow_debug.html @@ -0,0 +1,224 @@ + + + + + + + + Debugging Frame Reflow + + +

Debugging Frame Reflow HowTo

General Overview

The frame reflow can be logged with the debug capabilities implemented in nsFrame.cpp. +It provides the following information for each frame at the +start of its reflow +

reflow reason +
available width, available height +
computed width, computed height +
the previous and the next frame in flow +
and a count number. +

When the frame's reflow is finished the following information is displayed :

reflow metric (desired) width, height +
max. element size (MES) width +
maximum Width +
frame status +
overflow area +

+ +

Getting the log

Make sure that your build is a debug build. +
Create a text file (for instance reflow_rules.txt). +
Enter this line in the text file
```
* 1
```
+
Save the text file in the %DIST% directory +
Go to the %DIST% directory +
enter from command line: set GECKO_DISPLAY_REFLOW_RULES_FILE=reflow_rules.txt +
Run viewer > logfile.txt and load your testcase. The +logfile will contain all the promised information. +

Log File analyis

The logfile for a simple table like

+<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
+<html>
+<head>
+  <meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
+</head>
+<body>
+<table width="100">
+  <tbody>
+    <tr>
+      <td>foo</td>
+    </tr>
+  </tbody>
+</table>
+</body>
+</html>
+

+ +

will create the following log:

+VP 00B97C30 r=0 a=9180,4470 c=9180,4470 cnt=856 
+ scroll 00B97EE0 r=0 a=9180,4470 c=9180,4470 cnt=857 
+ scroll 00B97EE0 r=0 a=9180,4470 c=9180,4470 cnt=858 
+  canvas 00B97C6C r=0 a=9180,UC c=9180,4470 cnt=859 
+   area 02D7AFE4 r=0 a=9180,UC c=9180,UC cnt=860 
+    text 02D7B150 r=0 a=9180,UC c=UC,UC cnt=861 
+    text 02D7B150 d=0,0 
+    block 02D7B210 r=0 a=9180,UC c=8940,UC cnt=862 
+    block 02D7B210 d=8940,0 
+   area 02D7AFE4 d=9180,120 
+  canvas 00B97C6C d=9180,4470 
+ scroll 00B97EE0 d=9180,4470 
+ scroll 00B97EE0 d=9180,4470 
+VP 00B97C30 d=9180,4470 
+VP 00B97C30 r=1 a=9180,4470 c=9180,4470 cnt=863 
+ scroll 00B97EE0 r=1 a=9180,4470 c=9180,4470 cnt=864 
+ scroll 00B97EE0 r=1 a=9180,4470 c=9180,4470 cnt=865 
+  canvas 00B97C6C r=1 a=9180,UC c=9180,4470 cnt=866 
+   area 02D7AFE4 r=1 a=9180,UC c=9180,UC cnt=867 
+    block 02D7B210 r=1 a=9180,UC c=8940,UC cnt=868 
+     text 02D7B3F8 r=0 a=8940,UC c=UC,UC cnt=869 
+     text 02D7B3F8 d=0,0 
+     tblW 02D7B5F0 r=0 a=8940,UC c=0,0 cnt=870 
+      tbl 02D7B7EC r=0 a=8940,UC c=1500,UC cnt=871 
+       rowG 00B984A4 r=0 a=UC,UC c=UC,UC cnt=872 
+        row 02D7BAF8 r=0 a=UC,UC c=UC,UC cnt=873 
+         cell 02D7BC98 r=0 a=UC,UC c=UC,UC cnt=874 
+          block 02D7BCF8 r=0 a=UC,UC c=UC,UC cnt=875 
+           text 02D7BE84 r=0 a=UC,UC c=UC,UC cnt=876 
+           text 02D7BE84 d=300,285 me=300 
+          block 02D7BCF8 d=300,300 me=300 
+         cell 02D7BC98 d=330,330 me=330 
+        row 02D7BAF8 d=UC,330 
+       rowG 00B984A4 d=UC,330 
+       colG 02D7BFB0 r=0 a=UC,UC c=UC,UC cnt=877 
+        col 02D7C0D8 r=0 a=0,0 c=1500,UC cnt=878 
+        col 02D7C0D8 d=0,0 
+       colG 02D7BFB0 d=0,0 
+       rowG 00B984A4 r=2 a=1500,UC c=1500,UC cnt=879 
+        row 02D7BAF8 r=2 a=1500,UC c=1500,UC cnt=880 
+         cell 02D7BC98 r=2 a=1440,UC c=1410,UC cnt=881 
+          block 02D7BCF8 r=2 a=1410,UC c=1410,UC cnt=882 
+          block 02D7BCF8 d=1410,300 
+         cell 02D7BC98 d=1440,330 
+        row 02D7BAF8 d=1500,330 
+       rowG 00B984A4 d=1500,330 
+       colG 02D7BFB0 r=2 a=1500,UC c=1500,UC cnt=883 
+        col 02D7C0D8 r=0 a=0,0 c=1500,UC cnt=884 
+        col 02D7C0D8 d=0,0 
+       colG 02D7BFB0 d=0,0 
+      tbl 02D7B7EC d=1500,390 
+     tblW 02D7B5F0 d=1500,390 
+     text 02D7C130 r=0 a=8940,UC c=UC,UC cnt=885 
+     text 02D7C130 d=0,0 
+    block 02D7B210 d=8940,390 
+   area 02D7AFE4 d=9180,630 
+  canvas 00B97C6C d=9180,4470 
+ scroll 00B97EE0 d=9180,4470 
+ scroll 00B97EE0 d=9180,4470 
+VP 00B97C30 d=9180,4470 
+

+The first line shows the reflow of the viewport (VP). This viewport has the address 00B97C30. It is the initial reflow: r=0. Other reflow reasons are:

+ + + + + +

1	incremental reflow
2	resize reflow
3	style change reflow
4	dirty reflow.

+ +

The available width is 9180 twips. The available height is 4470 twips (a=9180,4470). The computed width is 9180 twips. The computed height is 4470 twips (c=9180,4470). The line count is 856 (cnt=856). +

+Below this is a line that reads:

tblW 02D7B5F0 r=0 a=8940,UC c=0,0 cnt=870

Here the UC shows that on initial reflow the available height for the table wrapper frame is unconstrained. +

+The table cell requires its children to compute the MES. It is reported back from the block as: +

block 02D7BCF8 d=300,300 me=300

The block max. element size is 300 twips. +

The second table reflow is started at +

rowG 00B984A4 r=2 a=1500,UC c=1500,UC cnt=879

where the previous information is used. +The block has been required to compute the max. element size only once and it reports now: +

block 02D7BCF8 d=1410,300

The block shows the same address as the previous one. +

Frames with children that overflow the parent will return PR_TRUE from HasOverflowRect(). For these frames +the overflow area is displayed as block 025ED8F0 d=8940,1020 o=(0,0) 9180 x 1020. The overflow area is specified as (x,y) origin and width x height. +

The reflow finishes at the same level where it started. + +

Advanced reflow debugging

The previously described technique dumps the data for every frame. Sometimes the log is clearer if only the main frames are shown. +The entries in the reflow log can be controlled on a frame level. For instance adding text 0 to the rules in reflow_rules.txt would hide the text entries from the reflow. The display of the following frames can be turned on by adding a line with the frame name and 1 or turned off by adding a line with the frame name and 0:

+ + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

short name	layout tag
area	area
block	block
br	br
bullet	bullet
button	gfxButtonControl
hr	hr
frameI	htmlFrameInner
frameO	htmlFrameOuter
img	image
inline	inline
letter	letter
line	line
select	select
obj	object
page	page
place	placeholder
canvas	canvas
root	root
scroll	scroll
caption	tableCaption
cell	tableCell
bcCell	bcTableCell
col	tableCol
colG	tableColGroup
tbl	table
tblW	tableWrapper
rowG	tableRowGroup
row	tableRow
textCtl	textInput
text	text
VP	viewport

Once the problem is reduced to a single frame level, placing a breakpoint at DisplayReflowEnterPrint in nsFrame.cpp is a very efficient way to step through + the reflow tree. + +

Other reflow debug options

+ +

GECKO_DISPLAY_REFLOW_FLAG_PIXEL_ERRORS

+Setting this option via set GECKO_DISPLAY_REFLOW_FLAG_PIXEL_ERRORS = 1 enables a verification for each coordinate value that the coordinates are aligned at pixel boundaries. +
+
+ row 0268A594 r=0 a=UC,UC c=UC,20 cnt=870 +VALUE 20 is not a whole pixel + cell 0268A6C0 r=0 a=UC,UC c=UC,15 cnt=871 + block 0268A764 r=0 a=UC,UC c=UC,UC cnt=872 + block 0268A764 d=0,0 me=0 + cell 0268A6C0 d=0,0 me=0 + row 0268A594 d=UC,20 +VALUE 20 is not a whole pixel + rowG 0268A02C d=UC,695 +VALUE 695 is not a whole pixel
+
+

+While unaligned values at the entrance of a frame reflow can be ignored, when they appear at the exit of a routine this can cause display errors like stray lines. OS2 is very vulnerable to pixel alignement errors as text is drawn on pixel boundaries. + +

GECKO_DISPLAY_REFLOW_INDENT_UNDISPLAYED_FRAMES

+Setting this option via set GECKO_DISPLAY_REFLOW_INDENT_UNDISPLAYED_FRAMES = 1 will cause an advance of the indent even for frames which are blocked via the reflow rules file. + + -- cgit v1.2.3