418937 - Regression: FF3.0b4pre calls twice to NPP_Print() when printing plugin

Status: RESOLVED INCOMPLETE

(Core :: Printing: Output, defect)

Description

[danielle.pham]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9b3pre) Gecko/2008011704 Minefield/3.0b3pre
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9b4pre) Gecko/2008022005 Minefield/3.0b4pre 

Regression: With latest FF3.0b4pre, FF calls twice to NPP_Print() when printing plugin.

This is not a problem with 3.0b3pre (Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9b3pre) Gecko/2008011704 Minefield/3.0b3pre).

Reproducible: Always

Steps to Reproduce:
1. Load any applet from http://java.sun.com/products/plugin/1.5.0/demos/plugin/applets.html (It's okay to use OJI plugin to reproduce problem).
2. Print the page while stepping into the code where NPP_Print() is called.
3.
Actual Results:  
NPP_Print() gets called twice for each print request.

Expected Results:  
NPP_Print() should only being called once by browser for each print request

Comment 1

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

Is this an actual problem?  NP_Print will get called twice so that alpha can be recovered and proper compositing done if necessary.  I can make things always call NP_Print only once, but all plugin content will then have an opaque white background.

Comment 2

[Robert O'Callahan (:roc) (email my personal email if necessary)]

I don't see why this would be a problem.

Comment 3

[danielle.pham]

Calling twice to NPP_Print() causes Plugin to respond twice to a single print request -- a performance degrade during printing especially considering large plugin contents that spread a few pages.

On Windows, Java Plugin responds to NPP_Print() in an off-screen rendering technique for high resolution. That is, by creating a DIB section and rendering it into an enh meta DC before the last step -- copying and stretching it to the provided DC.  

If quality of the print composition still requires copying DIB section twice to the real printer DC, then perhaps this twice copying should be done at Plugin's printing last step, instead of by browser calling in twice to plugin.
That can save plugin from preparing the DIB twice.

Also, this is a recent change only as I understand, so how was print composition's quality before?

This is a performance vs. quality of printing problem.
While it's good to come to an agreement, it's not as critical as getting plugin printing to work in general with FF3.

So if you could, please concentrate on bug https://bugzilla.mozilla.org/show_bug.cgi?id=418915 first. Thanks.  

Comment 4

[Robert O'Callahan (:roc) (email my personal email if necessary)]

I don't think we really care about print performance at all.

Comment 5

[Wayne Mery (:wsmwk)]

do you see this issue still with version 3.6 or 4.0 beta?

Comment 6

[Stephanie Daugherty [:sdaugherty]]

No response to needed information. -> incomplete report