[Gambas-user] printer problem

[Charlie Reinl]

Am Donnerstag, den 04.02.2010, 09:48 +0100 schrieb Doriano Blengino:
> Charlie Reinl ha scritto:
> > Salut,
> >
> > I still haven't solved the Draw.Text tab problem, but I'v a new one (a
> > problem).
> >
> > If you open the printer-setup the first time, the 'Print to printer' is
> > chosen, and the target-file behind 'Print to file' is empty.
> >
> > If you check 'Print to file' and fill the target-file and then you
> > switch back to 'Print to printer', the target-file field is disabled.
> > (Setup Printer.png)
> >
> > Everything seems to be alright. 
> >
> > But, and there is my new problem, in my code I can't see what should be
> > done. (printing 5 times to file, makes no sense)
> >
> > Where is the magic pointer, which shows me the chosen device?
> > (Printer Properties.png)
> >   
> For what I know about printing in gambas, things are as following.
> 
> You can set by code printer.file to print to a file (a postscript is 
> generated), or set printer.name to direct the printing to an actual 
> printer. If printer.file is non-empty, the printing will go to a file. 
> The same is true if those properties are set by the interactive setup 
> panel. After that, you don't have to worry about the destination, the 
> code is the same: you draw() on the printer, and the underlying software 
> will do what is appropriate.
> 
> Other properties let you to define other printing aspects, like page 
> format, b/w or color, and so on.
> 
> The properties Copies, FromPage and ToPage are different, because they 
> don't do anything - you should read them and do things accordingly. To 
> be more precise, FromPage and ToPage are exactly so (if you read that 
> the user has set FromPage=2 and ToPage=2, then your printing routine 
> should only print the page number 2, and then terminate). "Copies" 
> sometimes works, sometimes not, so I decided to read the number of 
> copies, reset it to 1, and print several copies myself. I mean: "Copies" 
> was sometimes working, sometimes was ignored, and sometimes messed up 
> the printing. If you choose to do multiple copies by code, don't forget 
> to reset Copies to 1.
> 
> About printing several copies to a file, I see nothing strange... a 
> postscript file should be generated, containing two or more identical 
> pages. If you feed that file to a printer, multiple identical pages get 
> out. But in the first attempt, I did it differently, and I crashed into 
> rewriting the same file several times, as you are arguing. Can't 
> remember if it was my fault or gambas or qt one. I solved all together 
> by invoking multiple times the subroutine which prints a single page, 
> inside a "draw.begin()" and "draw.end()".
> 
> About tabulators, I would take a single string to print, break it in 
> several sub-strings taking tabulators as separators, taking care that 
> two tabulators in a row *do* define an empty string, print the single 
> sub-strings, calculate the width of every string and advancing the 
> position to the next tab-stop. The general idea is something like that:
> 
>     1. Declare an array for tabulator stops and fill it with suitable 
> positions. Those positions can be freely set or be equally-spaced, 
> depends on the application; but anyway they depend on the resolution of 
> the printer. You can say "I want a tabstop every inch on paper", so your 
> positions will have values 1*Printer.Resolution, 2*Printer.Resolution 
> and so on. Or you could say "I want a tabulator stop to be wide as 8 
> spaces", and in that case you should take the width of a space (using 
> textwidth()), multiply it by 8 and then by Printer.Resolution. Or you 
> could say "I want a tabulator in the middle of the page and one at 3/4 
> of the page". So the first value will be Printer.Width/2 and the second 
> value will be Printer.Width*3/4.
> 
>     2. Declare a subroutine which prints a string at X,Y position, 
> taking tabs in account. It could look like this:
> 
> sub outtabstr(text as string, xpos as integer, ypos as integer)
>   dim toprint as string
>   dim tpos as integer
> 
>   while text<>"" do
>     ' search a tabulator
>     tpos = instr(text, "\9")
>     if tpos=0 then
>       ' no tabulators, print and exit
>       draw.text(text, xpos, ypos)
>       return
>     endif
> 
>        ' there is a tab. print the left part
>        toprint = left(text, tpos-1)          ' take the part to print
>        text = mid(text, tpos+1)             ' and delete it from the rest
>        draw.text(toprint, xpos, ypos)   ' printed
>        ' now advance the X position to a suitable position
>        xpos += draw.textwidth(toprint)   ' our virtual cursor now is here
>        tpos = 0
>        ' MAX_TABSTOPS refers to  an array 0-based
>        while tpos<MAX_TABSTOPS and xpos>=tabstops[tpos]
>           inc tpos
>        wend
>        if tpos>=MAX_TABSTOPS
>           ' no more stops defined. What to do?
>           xpos += 300
>        else
>           ' ok, move to that tab position
>           xpos = tabstops[tpos]
>        endif
>     wend
> end
> 
> The above code is not tested and has several problems. It does not work 
> with UTF8, it does not check for margins, does not go to the next line, 
> it does not return the position of the virtual cursor after having 
> printed a string. But the general idea should be correct.
> 
> Regards,
> Doriano

Salut Doriano,

finally got the time, better say toke the time, because wanted to finish
it. I worked out the Draw.Text tab problem.
Because of other circumstances, I worked out tow ways, first to replace
it (the "\t") in the string, second to do it in Draw.Text.

The attached example shows the two. And I'm not sure which one will be
used. It's for gambas2.

Your example worked fine, nearly  without changes (the "Do" made an
error), thanks.


-- 
Cordialement
Charlie
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