Fwd: [Vm-dev] Re: we need help for rome

From: [hidden email]

Date: April 18, 2010 8:15:05 PM GMT+02:00

To: [hidden email]

Subject: Re: [Vm-dev] Re: [Pharo-project] we need help for rome

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From: stephane ducasse <[hidden email]>

Date: April 18, 2010 8:14:58 PM GMT+02:00

To: Squeak Virtual Machine Development Discussion <[hidden email]>

Cc: [hidden email]

Subject: Re: [Vm-dev] Re: [Pharo-project] we need help for rome

Thanks Bert

I think only the first 4 inst vars are actually used by the plugin:

http://squeakvm.org/svn/squeak/trunk/platforms/unix/src/plugins/RomePlugin/RomePlugin.c

#define CanvasHandleIndex 0

#define CanvasTargetIndex 1

#define CanvasFlagsIndex 2

#define CanvasStrokeColorIndex 3

#define CanvasInstSize 8

how did you get that information? from the image side or C code?
Because I tried to see but unsure.

So on Linux, Rome does use the "right" size. John appears to have used a Sophie image to generate his Plugin, which makes this fail (though I could not find his Rome plugin in the Mac OS platform code so can't verify that theory).

Now I understand why alain could remove the instance variable when cleaning the image side.

The proper fix would be to modify RomePlugin class>>initializeInstVarIndices to not generate the indices, but simply hard-code only the used ones (setting CanvasInstSize to 4), and change the comparison John mentioned below to <=. Also remove the unused *Index class vars. Now that there are plugins in the wild, hard-coding the indices is a good idea anyway. During development, the flexible generator version was useful, but not anymore.

I browsed a bit the C code and I'm learning so may be my questions are not clever, but

- do we need the pango primitives for ROME?
Apparently Pango may use Cairo for fonts rendering but do Rome needs that?
So is it simpler to use fonts via pango than cairo.

- then what about FormInstSize?

(interpreterProxy->slotSizeOf(formOop)) < FormInstSize
does it mean

- the primitives we have access to are listed by
void* RomePlugin_exports[][3] = {

- how do we know that the plugin is somehow in sync with Cairo "latest" version?

Stef

- Bert -

On 18.04.2010, at 18:45, Stéphane Ducasse wrote:

John

how can I know the order and the iv that are used by the plugin?

Stef

On Apr 17, 2010, at 4:09 AM, John M McIntosh wrote:

(a) In Sophie   

RomeCanvas subclass: #RomePluginCanvas

instanceVariableNames: 'handle target flags strokeColor stack font fontSize fontMatrix currentFillColor currentBackColor glyphAccuracy cachedGlyphBlt cachedClearBlt drawRunPositions drawRunGlyph drawRunPointY'

classVariableNames: 'CachedTarget FlagFill FlagStro

(b) In Pharo

RomeCanvas subclass: #RomePluginCanvas

instanceVariableNames: 'handle target flags strokeColor stack font fontSize fontMatrix'

classVariableNames: 'FlagFill FlagStroke Registry'

poolDictionaries: ''

category: 'Rome-PluginCanvas'

Comment warning:

INST VAR ORDER IS KNOWN TO PLUGIN! DO NOT REARRANGE!

So in the plugin we have...

if (interpreterProxy->slotSizeOf(canvasOop)) < CanvasInstSize)

fail().

where CanvasInstSize is 13

but as you see in (b) the number of instance slots for the canvas Oops is  8.

8 < 13, oops you fail.

So where did the instance vars   currentFillColor currentBackColor glyphAccuracy cachedGlyphBlt cachedClearBlt

go? On purpose gone, refactored, old code. etc....

On 2010-04-16, at 1:37 PM, Stéphane Ducasse wrote:

On Apr 16, 2010, at 10:30 PM, John McIntosh wrote:

Well I'm just as puzzled as you since the primitive gets executed and you are using the same binary that was shipped with Sophie years back.

I like to hear that because I feel less idiot. :)