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Embedded PDF viewer?

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Manuel Leuenberger
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Embedded PDF viewer?

Manuel Leuenberger
Hi,

I want to view a PDF within Pharo. I found that Athens has a PDF canvas, but I have no idea how to use it. Is there a way to view a PDF within Pharo, so that I can scroll, zoom, click links etc. in the PDF?

Cheers,
Manuel


Stephane Ducasse-3
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Re: Embedded PDF viewer?

Stephane Ducasse-3
Hi manuel

So far I do not know if we have this is Pharo.
I imagine that we would have to build a renderer once we will have the
PDF reader from Christian library.

Stef

On Tue, Oct 10, 2017 at 8:58 PM, Manuel Leuenberger
<[hidden email]> wrote:
> Hi,
>
> I want to view a PDF within Pharo. I found that Athens has a PDF canvas, but I have no idea how to use it. Is there a way to view a PDF within Pharo, so that I can scroll, zoom, click links etc. in the PDF?
>
> Cheers,
> Manuel
>
>

Offray Vladimir Luna Cárdenas-2
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Re: Embedded PDF viewer?

Offray Vladimir Luna Cárdenas-2
I have been thinking about this. I don't know if you can have a VNC
client inside the image that can be used to render a PDF app, but that
would be my first approach, to leverage all the features in the current
PDF readers.

Cheers,

Offray


On 10/10/17 14:04, Stephane Ducasse wrote:

> Hi manuel
>
> So far I do not know if we have this is Pharo.
> I imagine that we would have to build a renderer once we will have the
> PDF reader from Christian library.
>
> Stef
>
> On Tue, Oct 10, 2017 at 8:58 PM, Manuel Leuenberger
> <[hidden email]> wrote:
>> Hi,
>>
>> I want to view a PDF within Pharo. I found that Athens has a PDF canvas, but I have no idea how to use it. Is there a way to view a PDF within Pharo, so that I can scroll, zoom, click links etc. in the PDF?
>>
>> Cheers,
>> Manuel
>>
>>
>


kilon.alios
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Re: Embedded PDF viewer?

kilon.alios
Implementation wise this may be possible through a hack, some OS windows can be semi trasparent , this make it possible to overlay one GUI element over the other in this case a PDF with basic scrolling handles. It should be possible with UFFI and some knowledge of OS GUI APIs. Probably much easier than having to implement the entire things in Pharo from scratch which would be ideal.

The overlay windows can change size according to the dimension of the Pharo windows so you can fool any pharo user thinking this is actually an internal Pharo window. This way even if the user resize or maximise the pharo window nothing messes up the Pharo gui. 

On Wed, Oct 11, 2017 at 12:04 AM Offray Vladimir Luna Cárdenas <[hidden email]> wrote:
I have been thinking about this. I don't know if you can have a VNC
client inside the image that can be used to render a PDF app, but that
would be my first approach, to leverage all the features in the current
PDF readers.

Cheers,

Offray


On 10/10/17 14:04, Stephane Ducasse wrote:
> Hi manuel
>
> So far I do not know if we have this is Pharo.
> I imagine that we would have to build a renderer once we will have the
> PDF reader from Christian library.
>
> Stef
>
> On Tue, Oct 10, 2017 at 8:58 PM, Manuel Leuenberger
> <[hidden email]> wrote:
>> Hi,
>>
>> I want to view a PDF within Pharo. I found that Athens has a PDF canvas, but I have no idea how to use it. Is there a way to view a PDF within Pharo, so that I can scroll, zoom, click links etc. in the PDF?
>>
>> Cheers,
>> Manuel
>>
>>
>
Ben Coman
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Re: Embedded PDF viewer?

Ben Coman
In reply to this post by Stephane Ducasse-3

> On Tue, Oct 10, 2017 at 8:58 PM, Manuel Leuenberger
> <[hidden email]> wrote:
> > Hi,
> >
> > I want to view a PDF within Pharo. I found that Athens has a PDF canvas, but I have no idea how to use it. Is there a way to view a PDF within Pharo, so that I can scroll, zoom, click links etc. in the PDF?
> >
> > Cheers,
> > Manuel


On Wed, Oct 11, 2017 at 3:04 AM, Stephane Ducasse <[hidden email]> wrote:
>
> Hi manuel
>
> So far I do not know if we have this is Pharo.
> I imagine that we would have to build a renderer once we will have the
> PDF reader from Christian library.
>
> Stef

A renderer will have great synergy with PDFTalk, but I think a proof of concept can be done independently.
I've been poking at this topic for a while looking for options.  Coincidentally a couple of days I discovered the PDFium library. 
I haven't had time yet to give it a run, but it seems a good candidate since...
* Its a successful commercial product by Foxit built into Chrome converted to open source with Google's backing for use in Chromium
       https://www.foxitsoftware.com/company/press.php?id=305  
* Its license is BSD style
       https://github.com/hfiguiere/pdfium/tree/master/public
* Although written in C++ it has a C interface
      https://github.com/hfiguiere/pdfium/blob/master/public/fpdfview.h
      * Search here on  " Function: "  to skim through
      * Proof of concept seems to only need these key functions...  
          * void    FPDF_RenderPageBitmap( FPDF_BITMAP bitmap,FPDF_PAGE page, ... )
          * FPDF_BITMAP    FPDFBitmap_Create( int width, int height, int alpha);
          * FPDF_PAGE   FPDF_LoadPage   ( FPDF_DOCUMENT document, int page_index )
          * FPDF_DOCUMENT   FPDF_LoadMemDocument   ( const void* data_buf ... )
          * void    FPDF_InitLibrary ()    
* Has a concise getting started for POC... 
      https://github.com/hfiguiere/pdfium/blob/master/docs/getting-started.md
* Maybe useful fork with V8 disabled by default 
* Master repo here
      https://pdfium.googlesource.com/pdfium/

So Pharo might load a PDF file into a ByteArray, pass that to FPDF_LoadMemDocument() & FPDF_LoadPage(), 
then get a bitmap back from FPDFBitmap_Create() & FPDF_RenderPageBitmap() and display the result in a Pharo window.

The rest of this week I'm working 12 hour days on a mine site.  I could try it out once I'm home, but in the meantime is anyone else keen to try it? 

cheers -ben
Ben Coman
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Re: Embedded PDF viewer?

Ben Coman


On Wed, Oct 11, 2017 at 2:03 PM, Ben Coman <[hidden email]> wrote:

> On Tue, Oct 10, 2017 at 8:58 PM, Manuel Leuenberger
> <[hidden email]> wrote:
> > Hi,
> >
> > I want to view a PDF within Pharo. I found that Athens has a PDF canvas, but I have no idea how to use it. Is there a way to view a PDF within Pharo, so that I can scroll, zoom, click links etc. in the PDF?
> >
> > Cheers,
> > Manuel


On Wed, Oct 11, 2017 at 3:04 AM, Stephane Ducasse <[hidden email]> wrote:
>
> Hi manuel
>
> So far I do not know if we have this is Pharo.
> I imagine that we would have to build a renderer once we will have the
> PDF reader from Christian library.
>
> Stef


[Edit: Update license link]
 
A renderer will have great synergy with PDFTalk, but I think a proof of concept can be done independently.
I've been poking at this topic for a while looking for options.  Coincidentally a couple of days I discovered the PDFium library. 
I haven't had time yet to give it a run, but it seems a good candidate since...
* Its a successful commercial product by Foxit built into Chrome converted to open source with Google's backing for use in Chromium
       https://www.foxitsoftware.com/company/press.php?id=305  
* Its license is BSD style 
       https://github.com/hfiguiere/pdfium/blob/master/LICENSE
* Although written in C++ it has a C interface
      https://github.com/hfiguiere/pdfium/blob/master/public/fpdfview.h
      * Search here on  " Function: "  to skim through
      * Proof of concept seems to only need these key functions...  
          * void    FPDF_RenderPageBitmap( FPDF_BITMAP bitmap,FPDF_PAGE page, ... )
          * FPDF_BITMAP    FPDFBitmap_Create( int width, int height, int alpha);
          * FPDF_PAGE   FPDF_LoadPage   ( FPDF_DOCUMENT document, int page_index )
          * FPDF_DOCUMENT   FPDF_LoadMemDocument   ( const void* data_buf ... )
          * void    FPDF_InitLibrary ()    
* Has a concise getting started for POC... 
      https://github.com/hfiguiere/pdfium/blob/master/docs/getting-started.md
* Maybe useful fork with V8 disabled by default 
* Master repo here
      https://pdfium.googlesource.com/pdfium/

So Pharo might load a PDF file into a ByteArray, pass that to FPDF_LoadMemDocument() & FPDF_LoadPage(), 
then get a bitmap back from FPDFBitmap_Create() & FPDF_RenderPageBitmap() and display the result in a Pharo window.

The rest of this week I'm working 12 hour days on a mine site.  I could try it out once I'm home, but in the meantime is anyone else keen to try it? 

cheers -ben
Ben Coman
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Re: Embedded PDF viewer?

Ben Coman
I'm looking into calling PDFium from Pharo via FFI.
Currently I'm stalled a bit since it doesn't have a shared-library target.

If you consider access to such a library would be useful to the community, 
please take a few moments to star this issue...

cheers -ben


P.S. Can anyone comment on calling into a static library via FFI?



On Wed, Oct 11, 2017 at 2:05 PM, Ben Coman <[hidden email]> wrote:


On Wed, Oct 11, 2017 at 2:03 PM, Ben Coman <[hidden email]> wrote:

> On Tue, Oct 10, 2017 at 8:58 PM, Manuel Leuenberger
> <[hidden email]> wrote:
> > Hi,
> >
> > I want to view a PDF within Pharo. I found that Athens has a PDF canvas, but I have no idea how to use it. Is there a way to view a PDF within Pharo, so that I can scroll, zoom, click links etc. in the PDF?
> >
> > Cheers,
> > Manuel


On Wed, Oct 11, 2017 at 3:04 AM, Stephane Ducasse <[hidden email]> wrote:
>
> Hi manuel
>
> So far I do not know if we have this is Pharo.
> I imagine that we would have to build a renderer once we will have the
> PDF reader from Christian library.
>
> Stef


[Edit: Update license link]
 
A renderer will have great synergy with PDFTalk, but I think a proof of concept can be done independently.
I've been poking at this topic for a while looking for options.  Coincidentally a couple of days I discovered the PDFium library. 
I haven't had time yet to give it a run, but it seems a good candidate since...
* Its a successful commercial product by Foxit built into Chrome converted to open source with Google's backing for use in Chromium
       https://www.foxitsoftware.com/company/press.php?id=305  
* Its license is BSD style 
       https://github.com/hfiguiere/pdfium/blob/master/LICENSE
* Although written in C++ it has a C interface
      https://github.com/hfiguiere/pdfium/blob/master/public/fpdfview.h
      * Search here on  " Function: "  to skim through
      * Proof of concept seems to only need these key functions...  
          * void    FPDF_RenderPageBitmap( FPDF_BITMAP bitmap,FPDF_PAGE page, ... )
          * FPDF_BITMAP    FPDFBitmap_Create( int width, int height, int alpha);
          * FPDF_PAGE   FPDF_LoadPage   ( FPDF_DOCUMENT document, int page_index )
          * FPDF_DOCUMENT   FPDF_LoadMemDocument   ( const void* data_buf ... )
          * void    FPDF_InitLibrary ()    
* Has a concise getting started for POC... 
      https://github.com/hfiguiere/pdfium/blob/master/docs/getting-started.md
* Maybe useful fork with V8 disabled by default 
* Master repo here
      https://pdfium.googlesource.com/pdfium/

So Pharo might load a PDF file into a ByteArray, pass that to FPDF_LoadMemDocument() & FPDF_LoadPage(), 
then get a bitmap back from FPDFBitmap_Create() & FPDF_RenderPageBitmap() and display the result in a Pharo window.

The rest of this week I'm working 12 hour days on a mine site.  I could try it out once I'm home, but in the meantime is anyone else keen to try it? 

cheers -ben
tesonep@gmail.com
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Re: Embedded PDF viewer?

tesonep@gmail.com
Hello Ben, 
   UFFI does not allow you to call static libraries. Static libraries are not executable per se, they need to be linked in another program.
As I know, the only way of using an static library from Pharo is to:
  - Build a plugin that wraps it.
  - Build a DLL exposing all the functions in the library and then they are used through UFFI. 

The second option is the easiest to me, but it depends how the library is built up. For example, if the library uses a lot of compile time code generation (like macros or templates) making a generic DLL is not so easy. 

I think it is better to see if not other project has already tackle this problem when using the desired static library. 

Cheers,
Pablo

On Sun, Nov 5, 2017 at 1:39 PM, Ben Coman <[hidden email]> wrote:
I'm looking into calling PDFium from Pharo via FFI.
Currently I'm stalled a bit since it doesn't have a shared-library target.

If you consider access to such a library would be useful to the community, 
please take a few moments to star this issue...

cheers -ben


P.S. Can anyone comment on calling into a static library via FFI?



On Wed, Oct 11, 2017 at 2:05 PM, Ben Coman <[hidden email]> wrote:


On Wed, Oct 11, 2017 at 2:03 PM, Ben Coman <[hidden email]> wrote:

> On Tue, Oct 10, 2017 at 8:58 PM, Manuel Leuenberger
> <[hidden email]> wrote:
> > Hi,
> >
> > I want to view a PDF within Pharo. I found that Athens has a PDF canvas, but I have no idea how to use it. Is there a way to view a PDF within Pharo, so that I can scroll, zoom, click links etc. in the PDF?
> >
> > Cheers,
> > Manuel


On Wed, Oct 11, 2017 at 3:04 AM, Stephane Ducasse <[hidden email]> wrote:
>
> Hi manuel
>
> So far I do not know if we have this is Pharo.
> I imagine that we would have to build a renderer once we will have the
> PDF reader from Christian library.
>
> Stef


[Edit: Update license link]
 
A renderer will have great synergy with PDFTalk, but I think a proof of concept can be done independently.
I've been poking at this topic for a while looking for options.  Coincidentally a couple of days I discovered the PDFium library. 
I haven't had time yet to give it a run, but it seems a good candidate since...
* Its a successful commercial product by Foxit built into Chrome converted to open source with Google's backing for use in Chromium
       https://www.foxitsoftware.com/company/press.php?id=305  
* Its license is BSD style 
       https://github.com/hfiguiere/pdfium/blob/master/LICENSE
* Although written in C++ it has a C interface
      https://github.com/hfiguiere/pdfium/blob/master/public/fpdfview.h
      * Search here on  " Function: "  to skim through
      * Proof of concept seems to only need these key functions...  
          * void    FPDF_RenderPageBitmap( FPDF_BITMAP bitmap,FPDF_PAGE page, ... )
          * FPDF_BITMAP    FPDFBitmap_Create( int width, int height, int alpha);
          * FPDF_PAGE   FPDF_LoadPage   ( FPDF_DOCUMENT document, int page_index )
          * FPDF_DOCUMENT   FPDF_LoadMemDocument   ( const void* data_buf ... )
          * void    FPDF_InitLibrary ()    
* Has a concise getting started for POC... 
      https://github.com/hfiguiere/pdfium/blob/master/docs/getting-started.md
* Maybe useful fork with V8 disabled by default 
* Master repo here
      https://pdfium.googlesource.com/pdfium/

So Pharo might load a PDF file into a ByteArray, pass that to FPDF_LoadMemDocument() & FPDF_LoadPage(), 
then get a bitmap back from FPDFBitmap_Create() & FPDF_RenderPageBitmap() and display the result in a Pharo window.

The rest of this week I'm working 12 hour days on a mine site.  I could try it out once I'm home, but in the meantime is anyone else keen to try it? 

cheers -ben





--
Pablo Tesone.
[hidden email]
aglynn42
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Re: Embedded PDF viewer?

aglynn42

Evince is pretty easy to embed.

 

Sent from Mail for Windows 10

 

From: [hidden email]
Sent: Sunday, November 5, 2017 10:25 AM
To: [hidden email]
Subject: Re: [Pharo-users] Embedded PDF viewer?

 

Hello Ben, 

   UFFI does not allow you to call static libraries. Static libraries are not executable per se, they need to be linked in another program.

As I know, the only way of using an static library from Pharo is to:

  - Build a plugin that wraps it.

  - Build a DLL exposing all the functions in the library and then they are used through UFFI. 

 

The second option is the easiest to me, but it depends how the library is built up. For example, if the library uses a lot of compile time code generation (like macros or templates) making a generic DLL is not so easy. 

 

I think it is better to see if not other project has already tackle this problem when using the desired static library. 

 

Cheers,

Pablo

 

On Sun, Nov 5, 2017 at 1:39 PM, Ben Coman <[hidden email]> wrote:

I'm looking into calling PDFium from Pharo via FFI.

Currently I'm stalled a bit since it doesn't have a shared-library target.

 

If you consider access to such a library would be useful to the community, 

please take a few moments to star this issue...

 

cheers -ben

 

 

P.S. Can anyone comment on calling into a static library via FFI?

 

 

 

On Wed, Oct 11, 2017 at 2:05 PM, Ben Coman <[hidden email]> wrote:

 

 

On Wed, Oct 11, 2017 at 2:03 PM, Ben Coman <[hidden email]> wrote:


> On Tue, Oct 10, 2017 at 8:58 PM, Manuel Leuenberger
> <[hidden email]> wrote:
> > Hi,
> >
> > I want to view a PDF within Pharo. I found that Athens has a PDF canvas, but I have no idea how to use it. Is there a way to view a PDF within Pharo, so that I can scroll, zoom, click links etc. in the PDF?
> >
> > Cheers,
> > Manuel


On Wed, Oct 11, 2017 at 3:04 AM, Stephane Ducasse <[hidden email]> wrote:
>
> Hi manuel
>
> So far I do not know if we have this is Pharo.
> I imagine that we would have to build a renderer once we will have the
> PDF reader from Christian library.
>
> Stef

 

[Edit: Update license link]

 

A renderer will have great synergy with PDFTalk, but I think a proof of concept can be done independently.
I've been poking at this topic for a while looking for options.  Coincidentally a couple of days I discovered the PDFium library. 

I haven't had time yet to give it a run, but it seems a good candidate since...
* Its a successful commercial product by Foxit built into Chrome converted to open source with Google's backing for use in Chromium
       https://www.foxitsoftware.com/company/press.php?id=305  
* Its license is BSD style 
       https://github.com/hfiguiere/pdfium/blob/master/LICENSE
* Although written in C++ it has a C interface
      https://github.com/hfiguiere/pdfium/blob/master/public/fpdfview.h
      * Search here on  " Function: "  to skim through
      * Proof of concept seems to only need these key functions...  
          * void    FPDF_RenderPageBitmap( FPDF_BITMAP bitmap,FPDF_PAGE page, ... )
          * FPDF_BITMAP    FPDFBitmap_Create( int width, int height, int alpha);
          * FPDF_PAGE   FPDF_LoadPage   ( FPDF_DOCUMENT document, int page_index )
          * FPDF_DOCUMENT   FPDF_LoadMemDocument   ( const void* data_buf ... )
          * void    FPDF_InitLibrary ()    
* Has a concise getting started for POC... 

      https://github.com/hfiguiere/pdfium/blob/master/docs/getting-started.md
* Maybe useful fork with V8 disabled by default 

* Master repo here
      https://pdfium.googlesource.com/pdfium/

So Pharo might load a PDF file into a ByteArray, pass that to FPDF_LoadMemDocument() & FPDF_LoadPage(), 

then get a bitmap back from FPDFBitmap_Create() & FPDF_RenderPageBitmap() and display the result in a Pharo window.

 

The rest of this week I'm working 12 hour days on a mine site.  I could try it out once I'm home, but in the meantime is anyone else keen to try it? 


cheers -ben

 

 



 

--

Pablo Tesone.
[hidden email]

 
Ben Coman
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Re: Embedded PDF viewer?

Ben Coman
Thx for the tip.  However Envice is GPLd to constrain its use. 

cheers -ben

On Mon, Nov 6, 2017 at 2:16 AM, Andrew Glynn <[hidden email]> wrote:

Evince is pretty easy to embed.

 

Sent from Mail for Windows 10

 

From: [hidden email]
Sent: Sunday, November 5, 2017 10:25 AM
To: [hidden email]
Subject: Re: [Pharo-users] Embedded PDF viewer?

 

Hello Ben, 

   UFFI does not allow you to call static libraries. Static libraries are not executable per se, they need to be linked in another program.

As I know, the only way of using an static library from Pharo is to:

  - Build a plugin that wraps it.

  - Build a DLL exposing all the functions in the library and then they are used through UFFI. 

 

The second option is the easiest to me, but it depends how the library is built up. For example, if the library uses a lot of compile time code generation (like macros or templates) making a generic DLL is not so easy. 

 

I think it is better to see if not other project has already tackle this problem when using the desired static library. 

 

Cheers,

Pablo

 

On Sun, Nov 5, 2017 at 1:39 PM, Ben Coman <[hidden email]> wrote:

I'm looking into calling PDFium from Pharo via FFI.

Currently I'm stalled a bit since it doesn't have a shared-library target.

 

If you consider access to such a library would be useful to the community, 

please take a few moments to star this issue...

 

cheers -ben

 

 

P.S. Can anyone comment on calling into a static library via FFI?

 

 

 

On Wed, Oct 11, 2017 at 2:05 PM, Ben Coman <[hidden email]> wrote:

 

 

On Wed, Oct 11, 2017 at 2:03 PM, Ben Coman <[hidden email]> wrote:


> On Tue, Oct 10, 2017 at 8:58 PM, Manuel Leuenberger
> <[hidden email]> wrote:
> > Hi,
> >
> > I want to view a PDF within Pharo. I found that Athens has a PDF canvas, but I have no idea how to use it. Is there a way to view a PDF within Pharo, so that I can scroll, zoom, click links etc. in the PDF?
> >
> > Cheers,
> > Manuel


On Wed, Oct 11, 2017 at 3:04 AM, Stephane Ducasse <[hidden email]> wrote:
>
> Hi manuel
>
> So far I do not know if we have this is Pharo.
> I imagine that we would have to build a renderer once we will have the
> PDF reader from Christian library.
>
> Stef

 

[Edit: Update license link]

 

A renderer will have great synergy with PDFTalk, but I think a proof of concept can be done independently.
I've been poking at this topic for a while looking for options.  Coincidentally a couple of days I discovered the PDFium library. 

I haven't had time yet to give it a run, but it seems a good candidate since...
* Its a successful commercial product by Foxit built into Chrome converted to open source with Google's backing for use in Chromium
       https://www.foxitsoftware.com/company/press.php?id=305  
* Its license is BSD style 
       https://github.com/hfiguiere/pdfium/blob/master/LICENSE
* Although written in C++ it has a C interface
      https://github.com/hfiguiere/pdfium/blob/master/public/fpdfview.h
      * Search here on  " Function: "  to skim through
      * Proof of concept seems to only need these key functions...  
          * void    FPDF_RenderPageBitmap( FPDF_BITMAP bitmap,FPDF_PAGE page, ... )
          * FPDF_BITMAP    FPDFBitmap_Create( int width, int height, int alpha);
          * FPDF_PAGE   FPDF_LoadPage   ( FPDF_DOCUMENT document, int page_index )
          * FPDF_DOCUMENT   FPDF_LoadMemDocument   ( const void* data_buf ... )
          * void    FPDF_InitLibrary ()    
* Has a concise getting started for POC... 

      https://github.com/hfiguiere/pdfium/blob/master/docs/getting-started.md
* Maybe useful fork with V8 disabled by default 

* Master repo here
      https://pdfium.googlesource.com/pdfium/

So Pharo might load a PDF file into a ByteArray, pass that to FPDF_LoadMemDocument() & FPDF_LoadPage(), 

then get a bitmap back from FPDFBitmap_Create() & FPDF_RenderPageBitmap() and display the result in a Pharo window.

 

The rest of this week I'm working 12 hour days on a mine site.  I could try it out once I'm home, but in the meantime is anyone else keen to try it? 


cheers -ben

 

 



 

--

Pablo Tesone.
[hidden email]

 
Ben Coman
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Re: Embedded PDF viewer?

Ben Coman
In reply to this post by tesonep@gmail.com
I've managed to build PDFium into a shared library on Ubuntu 16.04.  (I'll announce a blog post on this later.)
Now I'm considering the best bitmap format to bring the rendered page back into Pharo.  
I'm seeking advise on...

Q1. Looking at the two significant bitmap creation functions below from the C header file,
which of PDFium's bitmap formats is the best match for Pharo?

// Gray scale bitmap, one byte per pixel.
#define FPDFBitmap_Gray 1
// 3 bytes per pixel, byte order: blue, green, red.
#define FPDFBitmap_BGR 2
// 4 bytes per pixel, byte order: blue, green, red, unused.
#define FPDFBitmap_BGRx 3
// 4 bytes per pixel, byte order: blue, green, red, alpha.
#define FPDFBitmap_BGRA 4

typedef void* FPDF_BITMAP;


// Function: FPDFBitmap_CreateEx
//          Create a device independent bitmap (FXDIB)
// Parameters:
//          width       -   The number of pixels in width for the bitmap.
//                          Must be greater than 0.
//          height      -   The number of pixels in height for the bitmap.
//                          Must be greater than 0.
//          format      -   A number indicating for bitmap format, as defined
//                          above.
//          first_scan  -   A pointer to the first byte of the first line if
//                          using an external buffer. If this parameter is NULL,
//                          then the a new buffer will be created.
//          stride      -   Number of bytes for each scan line, for external
//                          buffer only.
// Return value:
//          The bitmap handle, or NULL if parameter error or out of memory.
// Comments:
//          Similar to FPDFBitmap_Create function, but allows for more formats
//          and an external buffer is supported. The bitmap created by this
//          function can be used in any place that a FPDF_BITMAP handle is
//          required.
//
//          If an external buffer is used, then the application should destroy
//          the buffer by itself. FPDFBitmap_Destroy function will not destroy
//          the buffer.
FPDF_BITMAP 
FPDFBitmap_CreateEx(
                                      int width,
                                      int height,
                                      int format,
                                      void* first_scan,
                                      int stride);


// Function: FPDFBitmap_Create
//          Create a device independent bitmap (FXDIB).
// Parameters:
//          width       -   The number of pixels in width for the bitmap.
//                          Must be greater than 0.
//          height      -   The number of pixels in height for the bitmap.
//                          Must be greater than 0.
//          alpha       -   A flag indicating whether the alpha channel is used.
//                          Non-zero for using alpha, zero for not using.
// Return value:
//          The created bitmap handle, or NULL if a parameter error or out of
//          memory.
// Comments:
//          The bitmap always uses 4 bytes per pixel. The first byte is always
//          double word aligned.
//
//          The byte order is BGRx (the last byte unused if no alpha channel) or
//          BGRA.
//
//          The pixels in a horizontal line are stored side by side, with the
//          left most pixel stored first (with lower memory address).
//          Each line uses width * 4 bytes.
//
//          Lines are stored one after another, with the top most line stored
//          first. There is no gap between adjacent lines.
//
//          This function allocates enough memory for holding all pixels in the
//          bitmap, but it doesn't initialize the buffer. Applications can use
//          FPDFBitmap_FillRect to fill the bitmap using any color.
FPDF_BITMAP   
FPDFBitmap_Create(
                                  int width,
                                  int height,
                                  int alpha);


// Function: FPDFBitmap_Destroy
//          Destroy a bitmap and release all related buffers.
// Parameters:
//          bitmap      -   Handle to the bitmap. Returned by FPDFBitmap_Create.
// Return value:
//          None.
// Comments:
//          This function will not destroy any external buffers provided when
//          the bitmap was created.
void FPDFBitmap_Destroy(FPDF_BITMAP bitmap);


Pharo's relevant class comments are...

* Bitmap - My instances provide contiguous storage of bits, primarily to hold the graphical data of Forms. Forms and their subclasses provide the additional structural information as to how the bits should be interpreted in two dimensions.

* Form - A rectangular array of pixels, used for holding images.  All pictures, including character images are Forms.  The depth of a Form is how many bits are used to specify the color at each pixel.  The actual bits are held in a Bitmap, whose internal structure is different at each depth.  
The supported depths (in bits) are 1, 2, 4, 8, 16, and 32.  The number of actual colors at these depths are: 2, 4, 16, 256, 32768, and 16 million.
Forms are indexed starting at 0 instead of 1; thus, the top-left pixel of a Form has coordinates 0@0.
Forms are combined using BitBlt.  See the comment in class BitBlt.  Forms that repeat many times to fill a large destination are InfiniteForms.

So it seems Bitmap is agnostic to the format stored inside it, and it is Form that interprets the bitmap format.  
A 32 bit depth Form seems an obvious choice, but I'm not sure about the alpha options.  


Q2. Tips on how to display such a bitmap in Pharo?

 I found this example...
   | extent form ptr |
   extent := 400@300.
   form := ExternalForm extent: extent depth: 32.
   ptr := ExternalAddress gcallocate: (extent x * extent y * 4). 
   form setManualSurfacePointer: ptr.
      "insert here call to PDFium to render page to bitmap" 
   Display displayScaledOn: form.
   form displayAt: 0@0.
   form destroySurface.

where in my case I guess the "ptr:="  line might be replaced by...
   ptr := ffi_FPDFBitmap_Create  
             width: extent x  
             height: extent y 
             alpha: 0.

or...
   ptr := ffi_FPDFBitmap_CreateEx 
                  width: extent x
                  height: extent y
                  format: ??
                  first_scan: 0
                  stride: 0

but it seems ExternalForm doesn't exist in Pharo 6. 
ExternalForm seems to have been taken over by OSSDL2ExternalForm... ??? 

* OSSDL2ExternalForm - An ExternalForm is a specialized Form whose pixel-data is stored in memory that the user provides a pointer to.  This can simply be memory on the C heap, or (the motivating use-case...) it can be a pointer that is temporarily "mapped" from GPU memory by an API such as OpenCL.
IMPORTANT: Moved form FFI to SDL2 because is not needed there anymore but OSWindow-SDL2 package uses it.
The user is responsible for both releasing the image-memory, as well as destroying the surface handle (perhaps the latter should be handled by automatic finalization).



Q3a. Are there any general guiding FFI principals whether its better to use memory allocated by the library, or memory allocated by Pharo?  Perhaps instead I should use...
   pharo_allocated := ExternalAddress gcallocate: (extent x * extent y * 4).
   ptr := ffi_FPDFBitmap_CreateEx 
                  width: extent x
                  height: extent y
                  format: ??
                  first_scan: pharo_allocated
                  stride: ??

Q3b. Is it possible/advisable to pin a Bitmap and pass it to an external library?  Maybe it would be preferable to do something like...
   aBitmap := Bitmap new: (extent x * extent y * 4).
   ptr := ffi_FPDFBitmap_CreateEx 
                  width: extent x
                  height: extent y
                  format: ??
                  first_scan: aBitmap pinnedAddress
                  stride: ??


cheers -ben


On Sun, Nov 5, 2017 at 11:24 PM, [hidden email] <[hidden email]> wrote:
Hello Ben, 
   UFFI does not allow you to call static libraries. Static libraries are not executable per se, they need to be linked in another program.
As I know, the only way of using an static library from Pharo is to:
  - Build a plugin that wraps it.
  - Build a DLL exposing all the functions in the library and then they are used through UFFI. 

The second option is the easiest to me, but it depends how the library is built up. For example, if the library uses a lot of compile time code generation (like macros or templates) making a generic DLL is not so easy. 

I think it is better to see if not other project has already tackle this problem when using the desired static library. 

Cheers,
Pablo

On Sun, Nov 5, 2017 at 1:39 PM, Ben Coman <[hidden email]> wrote:
I'm looking into calling PDFium from Pharo via FFI.
Currently I'm stalled a bit since it doesn't have a shared-library target.

If you consider access to such a library would be useful to the community, 
please take a few moments to star this issue...

cheers -ben


P.S. Can anyone comment on calling into a static library via FFI?



On Wed, Oct 11, 2017 at 2:05 PM, Ben Coman <[hidden email]> wrote:


On Wed, Oct 11, 2017 at 2:03 PM, Ben Coman <[hidden email]> wrote:

> On Tue, Oct 10, 2017 at 8:58 PM, Manuel Leuenberger
> <[hidden email]> wrote:
> > Hi,
> >
> > I want to view a PDF within Pharo. I found that Athens has a PDF canvas, but I have no idea how to use it. Is there a way to view a PDF within Pharo, so that I can scroll, zoom, click links etc. in the PDF?
> >
> > Cheers,
> > Manuel


On Wed, Oct 11, 2017 at 3:04 AM, Stephane Ducasse <[hidden email]> wrote:
>
> Hi manuel
>
> So far I do not know if we have this is Pharo.
> I imagine that we would have to build a renderer once we will have the
> PDF reader from Christian library.
>
> Stef


[Edit: Update license link]
 
A renderer will have great synergy with PDFTalk, but I think a proof of concept can be done independently.
I've been poking at this topic for a while looking for options.  Coincidentally a couple of days I discovered the PDFium library. 
I haven't had time yet to give it a run, but it seems a good candidate since...
* Its a successful commercial product by Foxit built into Chrome converted to open source with Google's backing for use in Chromium
       https://www.foxitsoftware.com/company/press.php?id=305  
* Its license is BSD style 
       https://github.com/hfiguiere/pdfium/blob/master/LICENSE
* Although written in C++ it has a C interface
      https://github.com/hfiguiere/pdfium/blob/master/public/fpdfview.h
      * Search here on  " Function: "  to skim through
      * Proof of concept seems to only need these key functions...  
          * void    FPDF_RenderPageBitmap( FPDF_BITMAP bitmap,FPDF_PAGE page, ... )
          * FPDF_BITMAP    FPDFBitmap_Create( int width, int height, int alpha);
          * FPDF_PAGE   FPDF_LoadPage   ( FPDF_DOCUMENT document, int page_index )
          * FPDF_DOCUMENT   FPDF_LoadMemDocument   ( const void* data_buf ... )
          * void    FPDF_InitLibrary ()    
* Has a concise getting started for POC... 
      https://github.com/hfiguiere/pdfium/blob/master/docs/getting-started.md
* Maybe useful fork with V8 disabled by default 
* Master repo here
      https://pdfium.googlesource.com/pdfium/

So Pharo might load a PDF file into a ByteArray, pass that to FPDF_LoadMemDocument() & FPDF_LoadPage(), 
then get a bitmap back from FPDFBitmap_Create() & FPDF_RenderPageBitmap() and display the result in a Pharo window.

The rest of this week I'm working 12 hour days on a mine site.  I could try it out once I'm home, but in the meantime is anyone else keen to try it? 

cheers -ben





--
Pablo Tesone.
[hidden email]
K K Subbu
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Re: Embedded PDF viewer?

K K Subbu
On Monday 13 November 2017 09:50 AM, Ben Coman wrote:
> I've managed to build PDFium into a shared library on Ubuntu 16.04.  
> (I'll announce a blog post on this later.)
> Now I'm considering the best bitmap format to bring the rendered page
> back into Pharo.

Have you considered importing PDFs as a sequence of compressed PNGs into
Pharo? If you not interested in twiddling pixels in the imported PDFs,
perhaps PNG may be sufficient. They take up lesser space and easier to
move around or re-export.

Regards .. Subbu

Ben Coman
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Re: Embedded PDF viewer?

Ben Coman


On Mon, Nov 13, 2017 at 6:03 PM, K K Subbu <[hidden email]> wrote:
On Monday 13 November 2017 09:50 AM, Ben Coman wrote:
I've managed to build PDFium into a shared library on Ubuntu 16.04.  (I'll announce a blog post on this later.)
Now I'm considering the best bitmap format to bring the rendered page back into Pharo.

 Have you considered importing PDFs as a sequence of compressed PNGs into Pharo? If you not interested in twiddling pixels in the imported PDFs, perhaps PNG may be sufficient. They take up lesser space and easier to move around or re-export.

Regards .. Subbu

Yes, I've certainly considered it.  Pragmatically, in my electrical career I deal with a lot of single page A3 PDF scans of schematic drawings, so pre-converting to a bitmap format outside of Pharo wouldn't lose much.   But I've wanted PDF rendering inside Pharo for *years* and finally got a sniff of a solid possibility - so I'm chasing it down.  It might not pan out like I imagine, but "Live programming PDF documents" seems like a catchy meme that the broader community may find intriguing.  

Really, I'm just curious about what might be possible and can only discover that by walking the way.

cheers -ben
Sean P. DeNigris
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Re: Embedded PDF viewer?

Sean P. DeNigris
Administrator
Ben Coman wrote
> I've wanted PDF rendering inside Pharo for *years* and finally got a
> sniff of a solid possibility - so I'm chasing it down.  It might not pan
> out like I imagine, but "Live programming PDF documents" seems like a
> catchy meme that the broader community may find intriguing.

Go, go, go!!



-----
Cheers,
Sean
--
Sent from: http://forum.world.st/Pharo-Smalltalk-Users-f1310670.html

Cheers,
Sean
Offray Vladimir Luna Cárdenas-2
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Re: Embedded PDF viewer?

Offray Vladimir Luna Cárdenas-2
In reply to this post by Ben Coman


On 13/11/17 06:59, Ben Coman wrote:
> "Live programming PDF documents" seems like a catchy meme that the
> broader community may find intriguing.  
>
> Really, I'm just curious about what might be possible and can only
> discover that by walking the way.

Certainly I would be interested in that catchy meme. Please keep us
updated and keep also the good work.

Thanks,

Offray

K K Subbu
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Re: Embedded PDF viewer?

K K Subbu
In reply to this post by Ben Coman
On Monday 13 November 2017 05:29 PM, Ben Coman wrote:
> Yes, I've certainly considered it.  Pragmatically, in my electrical
> career I deal with a lot of single page A3 PDF scans of schematic
> drawings, so pre-converting to a bitmap format outside of Pharo wouldn't
> lose much.

PDF deals with vector graphics, so bitmap conversion will be lossy. You
could import them as SVG instead use the existing classes for handling
SVG and XML.

HTH .. Subbu

Christian Haider
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Re: Embedded PDF viewer?

Christian Haider
In the end, you need to have bitmaps for the screen.
Rendering is the projection of vectors onto pixels.

But you don't want to lose the vectors, because you need them for interactions (mouse, keyboard focus).

I think that it is extremely sexy to have an interactive viewer for PDF!

Writing a renderer is a lot of work, although the newer Windows and Apple APIs make it a lot easier nowadays.
Still, you need to have an answer to color composition and irregular clipping paths (the hardest problems I think of. But there may be more).
And it must be fast enough for interactive applications...

I was hoping to use some existing renderer. I imagine that Bens approach can work well.

Although I didn’t do anything towards rendering myself, I am thinking of using PDF.js in an embedded browser.
PDF.js is used by many browsers and seems to be good enough by now.
And it would be not too bad to fiddle with JavaScript to connect it with the model in Smalltalk, I guess.
The problem is the browser embedding. Is this feasible in Pharo?

Happy hacking,
        Christian


> -----Ursprüngliche Nachricht-----
> Von: Pharo-users [mailto:[hidden email]] Im Auftrag
> von K K Subbu
> Gesendet: Dienstag, 14. November 2017 06:43
> An: Ben Coman <[hidden email]>
> Cc: Any question about pharo is welcome <[hidden email]>
> Betreff: Re: [Pharo-users] Embedded PDF viewer?
>
> On Monday 13 November 2017 05:29 PM, Ben Coman wrote:
> > Yes, I've certainly considered it.  Pragmatically, in my electrical
> > career I deal with a lot of single page A3 PDF scans of schematic
> > drawings, so pre-converting to a bitmap format outside of Pharo
> > wouldn't lose much.
>
> PDF deals with vector graphics, so bitmap conversion will be lossy. You could
> import them as SVG instead use the existing classes for handling SVG and
> XML.
>
> HTH .. Subbu



Ben Coman
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Re: Embedded PDF viewer?

Ben Coman
In reply to this post by Sean P. DeNigris
On 14 November 2017 at 00:18, Sean P. DeNigris <[hidden email]> wrote:

> Ben Coman wrote
>> I've wanted PDF rendering inside Pharo for *years* and finally got a
>> sniff of a solid possibility - so I'm chasing it down.  It might not pan
>> out like I imagine, but "Live programming PDF documents" seems like a
>> catchy meme that the broader community may find intriguing.
>
> Go, go, go!!
>
>
>
> -----
> Cheers,
> Sean

I've been distracted from this to play around with Bittrex trading.
In case someone feels inclined to take up the reins, I've blogged
about where I got up to.

Pharo PDF Rendering, part 1, building PDFium
http://blog.openinworld.com/2017/11/pharo-pdf-part-1/

Pharo PDF Rendering, part 2, UFFI interfacing PDFium
http://blog.openinworld.com/2018/02/pharo-pdf-part-2/

cheers -ben

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