2015-10-22 8:54 GMT+02:00 Esteban Lorenzano <estebanlm@gmail.com>:

Hi,

Sorry late response but yesterday I was not around.

> On 20 Oct 2015, at 18:42, stepharo <stepharo@free.fr> wrote:
>
> for the mooc videos I must use larger fonts.
> So I ended up hacking and changing the hardcoded number in default
>
> defaultRowHeight
>�� ^ 24
>
> rowHeight
>�� "This is the row height your rows will have. Cells answered in dataSource will be forced to have
>�� this height number... We force it instead allowing lists to have any height because the logic to
>�� calculate rows becomes complicated. Possible, but complicated :)"
>
>�� ^ rowHeight ifNil: [ self class defaultRowHeight ]
>
>
> Esteban two questions:
>
> - when I read the code of FTmorph I was thinking that a lot of it has not much to do with UI but looks like a model :).

this is not a question :)
in the case of rowHeight, it determines how the row looks (and not what it shows) then is UI (IMO)�� anyway I��m aware this is not 100% MVC but knowing the height of rows is very important to calculate in a fast way how many rows fit and get the rows from datasource (an operation that happens a lot so is convenient to have it as fast as possible (at least in a ��fast table��).
this do not supports variable height but that can be achieved by extending the table without compromising the performance of the parent(just very few use-cases need a variable height table).

Hum, from practical results playing with the FastTable core code:

- With varying height, if you know the start index, then you can fill the container fast by streaming over the data source, building the row morphs and adding the heights, stopping when you reach the end of the container.

- Current FastTable core code is very inefficient if #at: is slow on the data source

- What is hard is getting the vertical scrollbar right.

- Current FastTable core code does multiple passes on some of the row building / coordinates stuff for no clear reasons.

��

>
> - if I were about to manage the height of a row based on its actual contents where should I put it.

as described, you need to extend the functionality, this is not supported in current version (reason already explained).
For me, to support this you need to extend:

- rowHeight should be rowHeightFor: index
- visibleRows and around need to take first visible row height, then iterate one by one asking for the each row size.
- datasource needs to be extended with ��rowHeight: index��

It is not the only way to do it.

It at: is slow on the data source, then rowheight: will be slow.

��

> FTTableContainerMorph is containing what is visible but I wonder why it was asking this to the FastTable and to the elements displayed?

explained above: speed needs.

>
> Why the ContainerMorph does not ask the FTTableRowMorph for its height and it could be computed based on the font.
> I still did not get where the strings built.

I didn��t thought about, that��s why is not calculating font size :)
Also�� I cannot know your table will contain text�� that��s a task for the datasource, then (to answer appropriate row height)�� but it needs to be fast! :)

Thierry

��

Esteban

>
>
> may be here
>
> updateExposedRows
>
>�� ...
>
>�� | cell |
>�� cell := (self owner dataSource
>�� cellColumn: (columns at: columnIndex)
>�� row: rowIndex).
>�� cell width: (columnWidths at: columnIndex).
>
> We should add more comments to methods.
>
>
> Stef
>
>
>
> drawOn: canvas
>�� | x y cellWidth cellHeight rowsToDisplay rowSubviews highligtedRowIndexes primarySelectionIndex |
>
>�� self bounds ifNil: [ ^ self ]. "Nothing to show yet"
>�� self owner ifNil: [ ^ self ].
>
>�� x := self left + self class rowLeftMargin.
>�� y := self top.
>�� cellWidth := self width - self class rowLeftMargin.
>�� cellHeight := self owner rowHeight.
>�� ^^^^^^^^^^^^^^^^^^^^^^^
>
>�� highligtedRowIndexes :=
>�� self owner selectedRowIndexes,
>�� self owner highlightedRowIndexes.
>�� primarySelectionIndex := self owner selectedRowIndex.
>
>�� "For some superweird reason, calling #calculateExposedRows here instead in #changed (where
>�� it should be called) is 10x faster. Since the whole purpose of this component is speed, for
>�� now I'm calling it here and adding the #setNeedRecalculateRows mechanism.
>�� History, please forgive me."
>�� self updateAllRows.
>
>�� rowsToDisplay := self exposedRows.
>�� rowSubviews := OrderedCollection new: rowsToDisplay size + 1.
>�� headerRow ifNotNil: [
>�� headerRow bounds: (x@y extent: cellWidth@cellHeight).
>�� y := y + cellHeight + self owner intercellSpacing.
>�� rowSubviews add: headerRow ].
>
>�� rowsToDisplay keysAndValuesDo: [ :rowIndex :row | | visibleHeight |
>�� visibleHeight := cellHeight min: (self bottom - y).
>�� row bounds: (x@y extent: cellWidth@visibleHeight).
>�� y := y + visibleHeight + self owner intercellSpacing.
>�� rowSubviews add: ((highligtedRowIndexes includes: rowIndex)
>�� ifTrue: [
>�� "IMPORTANT: I need to set owner to nil because otherwise it will trigger an
>�� invalidation of the owner when adding morph to selectionMorph, causing an
>�� infinite loop"
>�� self
>�� toSelectionRow: (row privateOwner: nil)
>�� primary: primarySelectionIndex = rowIndex ]
>�� ifFalse: [ row ]) ].
>
>�� submorphs := rowSubviews asArray.
>�� super drawOn: canvas.
>�� needsRefreshExposedRows := false
>