Define ipdl and actor classes. Implementation of actors is added in subsequent
patches.
Control flow:
1. A user starts a printing job.
2. We create a PrintTarget to print web content page by page.
3. When printing pages:
a. PrintTarget, who lives in the chrome process, create a new FileDescriptor
and pass that FD to the content process.
b. The content process renders page contents into the given FD.
c. PrintTarget render that FD, which contains only one page, into a PDF
file.
d. PrintTaget asks PDFium process to convert that PDF file into EMF contents
by *ConvertToEMF*
e. The PDFium process converts the given PDF into EMF contents and send back
EMF contents by *ConvertToEMFDone*
f. PrintTaget playbacks that EMF onto a printer DC. One page is printed!
f. If all pages are printed, then finalize print job; Otherwise, loop back
to #a.
The control flow that we landed in bug 1370488 does not work like the flow
I described above.
In [1], we paint all pages into one single PDF file. After all pages are
rendered into this PDF file, we finalize the current print job, which means the
printing progress dialog is close. *Then* we start to convert that PDF into
EMF and print each EMF page onto printer DC. We can not cancel this conversion
task since the printing dialog is close, there is no UI allow us to do that.
One more serious problem is: since the printing progress dialog is close,
people think that printing is done, but actually it's not.
Except move EMF conversion to a dedicated process, named PDFium process, I will
also fix the behavior we landed in bug 1370488.
[1]
https://hg.mozilla.org/mozilla-central/rev/b611ec2a42bf
MozReview-Commit-ID: JAnmNc3gAVK
Define ipdl and actor classes. Implementation of actors is added in subsequent
patches.
Control flow:
1. A user starts a printing job.
2. We create a PrintTarget to print web content page by page.
3. When printing pages:
a. PrintTarget, who lives in the chrome process, create a new FileDescriptor
and pass that FD to the content process.
b. The content process renders page contents into the given FD.
c. PrintTarget render that FD, which contains only one page, into a PDF
file.
d. PrintTaget asks PDFium process to convert that PDF file into EMF contents
by *ConvertToEMF*
e. The PDFium process converts the given PDF into EMF contents and send back
EMF contents by *ConvertToEMFDone*
f. PrintTaget playbacks that EMF onto a printer DC. One page is printed!
f. If all pages are printed, then finalize print job; Otherwise, loop back
to #a.
The control flow that we landed in bug 1370488 does not work like the flow
I described above.
In [1], we paint all pages into one single PDF file. After all pages are
rendered into this PDF file, we finalize the current print job, which means the
printing progress dialog is close. *Then* we start to convert that PDF into
EMF and print each EMF page onto printer DC. We can not cancel this conversion
task since the printing dialog is close, there is no UI allow us to do that.
One more serious problem is: since the printing progress dialog is close,
people think that printing is done, but actually it's not.
Except move EMF conversion to a dedicated process, named PDFium process, I will
also fix the behavior we landed in bug 1370488.
[1]
https://hg.mozilla.org/mozilla-central/rev/b611ec2a42bf
MozReview-Commit-ID: JAnmNc3gAVK
Define ipdl and actor classes. Implementation of actors is added in subsequent
patches.
Control flow:
1. A user starts a printing job.
2. We create a PrintTarget to print web content page by page.
3. When printing pages:
a. PrintTarget, who lives in the chrome process, create a new FileDescriptor
and pass that FD to the content process.
b. The content process renders page contents into the given FD.
c. PrintTarget render that FD, which contains only one page, into a PDF
file.
d. PrintTaget asks PDFium process to convert that PDF file into EMF contents
by *ConvertToEMF*
e. The PDFium process converts the given PDF into EMF contents and send back
EMF contents by *ConvertToEMFDone*
f. PrintTaget playbacks that EMF onto a printer DC. One page is printed!
f. If all pages are printed, then finalize print job; Otherwise, loop back
to #a.
The control flow that we landed in bug 1370488 does not work like the flow
I described above.
In [1], we paint all pages into one single PDF file. After all pages are
rendered into this PDF file, we finalize the current print job, which means the
printing progress dialog is close. *Then* we start to convert that PDF into
EMF and print each EMF page onto printer DC. We can not cancel this conversion
task since the printing dialog is close, there is no UI allow us to do that.
One more serious problem is: since the printing progress dialog is close,
people think that printing is done, but actually it's not.
Except move EMF conversion to a dedicated process, named PDFium process, I will
also fix the behavior we landed in bug 1370488.
[1]
https://hg.mozilla.org/mozilla-central/rev/b611ec2a42bf
MozReview-Commit-ID: JAnmNc3gAVK
