The most efficient tool to claim that html-table code is the victim and not the source of layout bugs is a frame reflow debug log. Look there especially how the maxElementsize (MES) and desired size are propagated. michael@0: michael@0:
michael@0: Another way to debug the reflow process is implemented inside nsBlockFrame.cpp. It can be invoked by
michael@0: set GECKO_BLOCK_DEBUG_FLAGS=reflow
michael@0:
michael@0: The available options are: michael@0:
reflow
michael@0: really-noisy-reflow
michael@0: max-element-size
michael@0: space-manager
michael@0: verify-lines
michael@0: damage-repair
michael@0: lame-paint-metrics
michael@0: lame-reflow-metrics
michael@0: disable-resize-opt
michael@0:
michael@0: These options can be combined with a comma separated list
michael@0: Messages generated by the reflow switch:
michael@0:
Block(div)(1)@00BE5AC4: reflowing dirty lines computedWidth=9000 computedHeight=1500
michael@0: nsresult nsBlockFrame::ReflowDirtyLines(nsBlockReflowState& aState)
michael@0: michael@0: The table layout strategy can be visualized by defining in the makefiles the constant DEBUG_TABLE_STRATEGY. michael@0: michael@0: If one takes for instance the following table michael@0:
| rendering | code | ||||
|---|---|---|---|---|---|
michael@0:
|
michael@0: michael@0: <table border width="300"> michael@0: <colgroup> michael@0: <col> michael@0: <col width="50%"> michael@0: <col width="1*"> michael@0: <col> michael@0: </colgroup> michael@0: <tr> michael@0: <td style="width:80px">cell 1</td> michael@0: <td>cell 2</td> michael@0: <td>cell 3</td> michael@0: <td>cell 4</td> michael@0: </tr> michael@0: </table> michael@0:michael@0: |
michael@0:
michael@0: it will produce the following log at the entrance of AssignNonPctColWidths:
michael@0:
michael@0:
michael@0: michael@0: AssignNonPctColWidths en max=4500 count=0 michael@0: ***START TABLE DUMP*** michael@0: mColWidths=-1 -1 -1 -1 michael@0: michael@0: col frame cache -> michael@0: 0=00B93138 1=00B931F0 2=024DD728 3=024DD780 michael@0: **START COL DUMP** colIndex=0 isAnonymous=0 constraint=0 michael@0: widths=-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 **END COL DUMP** michael@0: **START COL DUMP** colIndex=1 isAnonymous=0 constraint=0 michael@0: widths=-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 **END COL DUMP** michael@0: **START COL DUMP** colIndex=2 isAnonymous=0 constraint=0 michael@0: widths=-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 **END COL DUMP** michael@0: **START COL DUMP** colIndex=3 isAnonymous=0 constraint=0 michael@0: widths=-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 **END COL DUMP** michael@0: ***END TABLE DUMP*** michael@0:michael@0: |
michael@0: The en stands for entrance (ex for leaving a routine). The first line of the data dump shows that no width has yet been assigned to the columns mColWidths=-1 -1 -1 -1, -1 stands for:
michael@0:
michael@0: #define WIDTH_NOT_SET -1 michael@0:michael@0:
michael@0: This is followed by a reference to the column frame pointers: michael@0:
michael@0:
michael@0: col frame cache -> michael@0: 0=00B93138 1=00B931F0 2=024DD728 3=024DD780 michael@0:michael@0:
michael@0: This is followed by the information which width has been set for each column. The index of the column, whether it is anonymous and what kind of constrained has been appliedcolIndex=0 isAnonymous=0 constraint=0. The following constraint types are known: michael@0:
michael@0:
michael@0: eNoConstraint = 0, michael@0: ePixelConstraint = 1, // pixel width michael@0: ePercentConstraint = 2, // percent width michael@0: eProportionConstraint = 3, // 1*, 2*, etc. cols attribute assigns 1* michael@0: e0ProportionConstraint = 4 // 0*, means to force to min width michael@0:michael@0:
michael@0: After this follows the width information for each column: michael@0:
michael@0:
michael@0: widths=-1 -1 -1 -1 -1 -1 -1 -1 -1 -1 michael@0:michael@0:
michael@0: The table code knows ten different width's: michael@0:
michael@0: #define NUM_WIDTHS 10 michael@0: #define NUM_MAJOR_WIDTHS 3 // MIN, DES, FIX michael@0: #define MIN_CON 0 // minimum width required of the content + padding michael@0: #define DES_CON 1 // desired width of the content + padding michael@0: #define FIX 2 // fixed width either from the content or cell, col, etc. + padding michael@0: #define MIN_ADJ 3 // minimum width + padding due to col spans michael@0: #define DES_ADJ 4 // desired width + padding due to col spans michael@0: #define FIX_ADJ 5 // fixed width + padding due to col spans michael@0: #define PCT 6 // percent width of cell or col michael@0: #define PCT_ADJ 7 // percent width of cell or col from percent colspan michael@0: #define MIN_PRO 8 // desired width due to proportional <col>s or cols attribute michael@0: #define FINAL 9 // width after the table has been balanced, considering all of the others michael@0:michael@0:
michael@0: In the last log snippet none of these width's has been set. michael@0: Leaving AssignNonPctColWidths shows that already to all columns a width of 360 twips has been assigned michael@0:
michael@0: AssignNonPctColWidths ex michael@0: ***START TABLE DUMP*** michael@0: mColWidths=360 360 360 360 michael@0: michael@0: col frame cache -> michael@0: 0=00B93138 1=00B931F0 2=024DD728 3=024DD780 michael@0: **START COL DUMP** colIndex=0 isAnonymous=0 constraint=0 michael@0: widths=360 540 1230 -1 -1 -1 -1 -1 -1 360 **END COL DUMP** michael@0: **START COL DUMP** colIndex=1 isAnonymous=0 constraint=0 michael@0: widths=360 540 -1 -1 -1 -1 -1 -1 -1 360 **END COL DUMP** michael@0: **START COL DUMP** colIndex=2 isAnonymous=0 constraint=3 michael@0: widths=360 540 -1 -1 -1 -1 -1 -1 540 360 **END COL DUMP** michael@0: **START COL DUMP** colIndex=3 isAnonymous=0 constraint=0 michael@0: widths=360 540 -1 -1 -1 -1 -1 -1 -1 360 **END COL DUMP** michael@0: ***END TABLE DUMP*** michael@0:michael@0:
michael@0: The first column has already the minimum content width, the table column can't shrink below that, the desired content width of 540 twips, that's the space to layout cell 1 without wrapping the text and the 1230 which correspond to the style="width:80px" at the first cell. At this step the final size is 360 twips.
michael@0:
michael@0:
| MIN_CON | DES_CON | FIX | MIN_ADJ | DES_ADJ | FIX_ADJ | PCT | PCT_ADJ | MIN_PRO | FINAL | michael@0:
|---|---|---|---|---|---|---|---|---|---|
| 360 | 540 | 1230 | -1 | -1 | -1 | -1 | -1 | -1 | 360 |
michael@0: There was no change till the entrance of BalanceColumnWidths
michael@0:
michael@0:
michael@0:
michael@0: BalanceColumnWidths en count=1 michael@0: ***START TABLE DUMP*** michael@0: mColWidths=360 360 360 360 michael@0: michael@0: col frame cache -> michael@0: 0=00B93138 1=00B931F0 2=024DD728 3=024DD780 michael@0: **START COL DUMP** colIndex=0 isAnonymous=0 constraint=0 michael@0: widths=360 540 1230 -1 -1 -1 -1 -1 -1 360 **END COL DUMP** michael@0: **START COL DUMP** colIndex=1 isAnonymous=0 constraint=0 michael@0: widths=360 540 -1 -1 -1 -1 -1 -1 -1 360 **END COL DUMP** michael@0: **START COL DUMP** colIndex=2 isAnonymous=0 constraint=3 michael@0: widths=360 540 -1 -1 -1 -1 -1 -1 540 360 **END COL DUMP** michael@0: **START COL DUMP** colIndex=3 isAnonymous=0 constraint=0 michael@0: widths=360 540 -1 -1 -1 -1 -1 -1 -1 360 **END COL DUMP** michael@0: ***END TABLE DUMP*** michael@0:michael@0:
michael@0: But at the end the final distribution between the columns has been reached. michael@0:
michael@0:
michael@0: BalanceColumnWidths ex michael@0: ***START TABLE DUMP*** michael@0: mColWidths=1230 2160 465 465 michael@0: michael@0: col frame cache -> michael@0: 0=00B93138 1=00B931F0 2=024DD728 3=024DD780 michael@0: **START COL DUMP** colIndex=0 isAnonymous=0 constraint=0 michael@0: widths=360 540 1230 -1 -1 -1 -1 -1 -1 1230 **END COL DUMP** michael@0: **START COL DUMP** colIndex=1 isAnonymous=0 constraint=0 michael@0: widths=360 540 -1 -1 -1 -1 2160 -1 -1 2160 **END COL DUMP** michael@0: **START COL DUMP** colIndex=2 isAnonymous=0 constraint=3 michael@0: widths=360 540 -1 -1 -1 -1 -1 -1 540 465 **END COL DUMP** michael@0: **START COL DUMP** colIndex=3 isAnonymous=0 constraint=0 michael@0: widths=360 540 -1 -1 -1 -1 -1 -1 -1 465 **END COL DUMP** michael@0: ***END TABLE DUMP*** michael@0:michael@0:
michael@0: The column dump is implemented in nsTableColFrame.cpp in the routine:
michael@0: void nsTableColFrame::Dump(int32_t aIndent).
michael@0:
michael@0:
needs to be written michael@0: michael@0:
author: Bernd Mielke
2002-06-05