315383 - Elements with coordinates >= 32768 not drawn

Status: RESOLVED FIXED

(Core :: SVG, defect)

Description

[Paul Hopgood]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8) Gecko/20051025 Firefox/1.5
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8) Gecko/20051025 Firefox/1.5

Lines that substantially exceed the SVG view box are not shown.
It would appear coordinates are being truncated to a 16bit number somewhere as line of length less than 32767 (after any scaling) are ok but lines of 32768 or longer (after any scaling) are not shown. 

Reproducible: Always

Steps to Reproduce:
I'll attach an example file.
Actual Results:  
The attached file should display 6 horizontal lines, a pair of red, a pair of green and a pair of blue.

Expected Results:  
Only the *slightly* shorter blue lines are displayed.

The red and green lines hould be displayed.

Comment 1

[Jonathan Watt [:jwatt]]

Sounds like this is due to cairo's internal limits.

Comment 2

[Adam Guthrie]

*** Bug 315382 has been marked as a duplicate of this bug. ***

Comment 3

[Paul Hopgood]

Attachment: Should draw six horizontal lines

This SVG file should show six horizontal lines, a pair of red, a pair green and a pair of blue. But only the blue lines are shown just because they are one pixel shorter!

Comment 4

[Hermann Schwab]

confirming Branch and Trunk: 
Mozilla/5.0 (Windows; U; Win98; en-US; rv:1.8) Gecko/20051025 Firefox/1.5
Mozilla/5.0 (Windows; U; Win98; en-US; rv:1.9a1) Gecko/20051104 Firefox/1.6a1

WFM Mozilla/5.0 (Windows; U; Win98; en-US; rv:1.9a1) Gecko/20051106 SeaMonkey/1.5a

At first, Mozilla also only renders two blue lines. After some seconds, different colored lines are rendered above and below each blue line. Didn´t see how long it took, as I tested Firefox in the meantime.

Comment 5

[Ben Fowler]

Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.9a1) Gecko/20051106 Firefox/1.6a1

WFM

Comment 6

[JP Fiset]

Look also at Bug 381875

Comment 9

[Jonathan Watt [:jwatt]]

I think Arpad's summary is more useful, so using that here.

Comment 10

[Arpad Borsos [:Swatinem]]

BTW, this is what the spec ( http://www.w3.org/TR/SVG/types.html#BasicDOMInterfaces ) says:
Unless stated otherwise for a particular attribute or property, a <number> has the capacity for at least a single-precision floating point number (see [ICC32]) and has a range (at a minimum) of -3.4e+38F to +3.4e+38F.
It is recommended that higher precision floating point storage and computation be performed on operations such as coordinate system transformations to provide the best possible precision and to prevent round-off errors.
Conforming High-Quality SVG Viewers are required to use at least double-precision floating point (see [ICC32]) for intermediate calculations on certain numerical operations.

Can someone tell me what +3.4e+38F means as int?

Comment 11

[JP Fiset]

It would be 

340 [insert 33 zeros] 000

Comment 12

[Vladimir Vukicevic [:vlad] [:vladv] (needinfo me, slow to respond)]

This is due to the internal Cairo precision that's used in Fx2 being 16.16 fixed point; that is, you only have 32768 pixels to work with.  This sucks, and we're working on fixing it.  Most likely, for Fx3, this will become 24.8, or 16,777,216.0 pixels.  This is -still- not ideal, but it will be much harder to accidentally hit.

Linux users will probably not see this fixed in Fx3, because the Render extension specifies 16.16 fixed as part of its API; its' not possible to send bigger coordinates down to X.

Comment 15

[Robert Longson [:longsonr]]

It looks like Firefox 3 will be 24.8. i.e. it will have a coordinate range of ±33,554,432. The nightlies have this range now.


The testcase in this bug now works as do those in the various duplicates of this bug.

Comment 16

[Robert Longson [:longsonr]]

fixed by check in for bug 384681