Problem with CairoCanvas pdf text
lazarus / 39-Graphics

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ph2 · 2016-11-10 08:06

Hello! I've encountered a problem with CairoCanvas printing out some
longer texts out incorrectly when ran on Debian, but working correctly
on Ubuntu etc. Text on Debian is printed far left outside the pdf
paper area and clipped out, while it is correctly printed on Ubuntu.
This is my reduced example code:

Code: Pascal  [Select][+][-]window.onload = function(){var x1 =
document.getElementById("main_content_section"); if (x1) { var x =
document.getElementsByClassName("geshi");for (var i = 0; i ...type 
TTempCairoPdfCanvas = class(TCairoPdfCanvas) ... constructor
TTempCairoPdfCanvas.Create;begin  inherited Create; 
Stream:=TMemoryStream.Create;  CreateHandle;end;            
 procedure TForm1.Button1Click(Sender: TObject);var   FDoc:
TTempCairoPdfCanvas;   Rect: TRect;   FileStream: TFileStream;begin 
FDoc := TTempCairoPdfCanvas.Create;  Rect.Left := 36;  Rect.Right :=
503;  Rect.Top := 107;  Rect.Bottom := 123;  FDoc.BeginDoc; 
//FDoc.Font.Name:='Times';  FDoc.Font.Name:='Arial'; 
FDoc.Font.Size:=12;  FDoc.Font.Color:=clBlack;  FDoc.Font.Orientation
:= 0;   FDoc.Brush.Color:=clBlack;  FDoc.TextRect(Rect, 36, 107, 'Some
bit longer text to print out to a pdf file here like this, hope it
will print out fine.', FDoc.TextStyle);  FDoc.EndDoc;  FileStream :=
TFileStream.Create('./test.pdf', fmCreate);  FDoc.Stream.Seek(0,
fsFromBeginning);  FileStream.CopyFrom(FDoc.Stream,
FDoc.Stream.Size);  FileStream.Free;  OpenDocument('./test.pdf');end;
Basically creating a canvas and drawing text on it, then saving the
stream to a file. On Ubuntu it works fine, the whole text prints on
the page but on Debian, the text only shows 'will print out fine.'
When I change the font to Times, now it prints it out fine on Debian
as well. Any clue why this might be happening?

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Graeme · 2016-11-10 14:47

Any specific reason you are using CairoPDFCanvas? If not, try fcl-pdf
included with FPC (trunk) and will be included with FPC 3.0.2 as well.
The code can be copied from FPC (trunk) and used with FPC 2.6.4 as
well. The PDF results is consistent no matter the platform. We also
tested with about 8 different PDF viewers.

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ph2 · 2016-11-11 07:06

CairoCanvas is used in production code inherited from someone else,
currently compiled with FPC 2.6.4. It might be possible to replace it
with another package like fcl-pdf with some effort though, but it will
require bit of testing to implement.

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marcov · 2016-11-11 08:10

Afaik when a font can't be found, the X system grabs the "nearest"
one?

So maybe it is a question of making sure the fontpackage with "arial"
is also installed on debian? (I assume it is in the fontpackage
released by MS?)

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ph2 · 2016-11-11 08:36

I've already installed the Microsoft TrueType core fonts on Debian,
didn't change the behaviour before or after. Tested with other famous
Microsoft fonts and the text drawing works as expected on other fonts
than Arial or Verdana. These two seem to split the text to two lines
and draw the first line above the clipped rectangle on the pdf?

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Graeme · 2016-11-11 09:13

I don't know CairoPDFCanvas, but does it adhere to the license of the
font? Some fonts don't allow embedding, and fcl-pdf will prevent such
fonts from being embedded in a PDF. Then again, if you see partial
text using Arial, then it's probably not that. I'm just thinking out
loud here. ;-)

Again, never used CairoPDFCanvas... How does it know what size Canvas
you have? From your code sameple I don't see anything related to the
available "canvas" size? Or does CairoPDFCanvas automatically make a
canvas large enough for all its content to fit on? With fcl-pdf you
set the page size and orientation, and that tells TPDFDocument what
space you have to render content per page.