[reportlab-users] Issues related to setting parameters of graphs, lines, and rectangles, and they are not printing correctly

[J. R. Carroll]

Also, I still need help with:

I found canvas.setDash() for setting dashed lines, but I am using a

> Drawing() and adding shapes.Lines() to the Drawing, then renderingPDF to my

> canvas - maybe it is the way I have wrapped everything (wrapped in terms of

> loops, classes, and functions), but I cannot get shapes.Lines to be dashed

> (or dotted or any other style other than a Line - which makes sense -

> kinda)...

>


If anyone has an answer to this, that would be awesome!  (or Tim/Andy if
you answered and I didn't see it - sorry!)

-J


----


J. R. Carroll
Independent Researcher through Hurtz Labs
Research Methods, Test Development, and Statistics
www.jrcresearch.net
Cell:  (650) 776-6613
Email: jrcarroll at jrcresearch.net
          jrcarroll at hurtzlab.com
          jrc.csus at gmail.com





On Thu, Nov 29, 2012 at 8:44 PM, J. R. Carroll <jrcarroll at jrcresearch.net>wrote:


> OK, so I'm a day late replying!  Sorry - work and all =P

>

> Alright - some updates - it turns out the problem of having stroke widths

> that were really small was not a problem of reportlab, but rather the

> grayscale conversion on our printers; it was trying to convert colors to

> grayscale and it was causing some really nasty antialiasing issues which

> made some grid lines disappear when printed - it created a plaid-like

> pattern, and it was VERY frustrating to diagnose!

>

> The solution was to print in a different color.  Since I was using the

> colors dict from reportlab which has a ton of colors to select from without

> having to input RGB/CMYK values, it was a pretty simple fix.  However, I

> tried this at one of the earliest stages of debugging this nasty anomaly!

>  The reason I dismissed colors so quickly was that I started off in pink -

> saw the issue at the printer, thought "hmmm - maybe it's the colors" and

> changed it to red.  Well red doesn't print very well on all of our printers

> (Cannon, and HP) - and yes, looking back I see how quickly I dismissed it

> especially with how close pink and red are in terms of printer ink -

> but!!!!  there's more!!  =P  It's not the inks fault!  We have plenty of

> ink, remember these were being printed in grayscale so color wasn't the

> issue!  It was the color<=>grayscale conversion that was the issue.

>

> The solution:  change the color

>

> The next problem:  now we have to find a balance between "what looks good

> on the screen" and "what looks good on print" (in both grayscale and

> color).

>

> The partial-solution:  I created a script that will retrieve all the

> colors in reportlab, print a small sample grid + the color name + color RGB

> values, neatly print them on several PDF pages (thanks to ReportLab!).  As

> soon as I did this and sent to to multiple printers - we are seeing which

> colors are working across the sample of available print medias we have, and

> what looks good on the screen!  This script/PDF calibrator is really a

> god-send.  I don't know if anyone else will ever have use for it, or if

> there are better scripts out there that do the exact same thing, but this

> is really helping us a lot over the next few days.

>

> If anyone is interested in seeing the output and has access to several

> printers (particular the business grayscale printers you are likely to find

> in a corporation - i.e. Cannon and HP "monsters") download my script, and

> open the resulting PDF (or I can email you the contents of the script in

> case you don't feel comfortable downloading something from my personal

> website).  Either way, I hope someone can make use of this solution - I

> know my desk is happy that I'm not pounding my bloody forehead into it

> anymore!

>

> Script is available for download from:

> http://www.jrcresearch.net/downloads/scripts.zip

>

> If anyone has ideas on how to improve it - let me know.  I'm already

> thinking of other neat printer calibration test prints I can add to this!

>

> -J

> ----

>

>

> J. R. Carroll

> Independent Researcher through Hurtz Labs

> Research Methods, Test Development, and Statistics

> www.jrcresearch.net

> Cell:  (650) 776-6613

> Email: jrcarroll at jrcresearch.net

>           jrcarroll at hurtzlab.com

>           jrc.csus at gmail.com

>

>

>

>

>

> On Wed, Nov 28, 2012 at 2:38 PM, Andy Robinson <andy at reportlab.com> wrote:

>

>> On 28 November 2012 21:35, J. R. Carroll <jrcarroll at jrcresearch.net>wrote:

>>

>>> I'm on my way out, and would be happy to compile all this information

>>> tomorrow morning, but I think I found the problem.  Apparently, neither

>>> printer I was using (nor any printer I have access to) liked color.pink.  I

>>> don't think it was ReportLab (and I'm sure you have more insight than I),

>>> but the grayscale handling at the printer just mucked everything up (where

>>> muck = some fancy tech lingo I can't think of right now).  As soon as I

>>> changed the grid color from color.pink to color.black - the grid looks

>>> perfect - really makes it look like I know what I am doing (jokes on them!).

>>>

>>> I think that this might be falling outside the ReportLab domain, but!

>>> might you have any recommendations for handling color documents to a

>>> black/white printer?  Do some colors print better than others - or is that

>>> really a function of the printer?

>>>

>>>

>> First question is whether the printer uses the CMYK colour model, or RGB.

>>  High end ones for artwork tend to be CMYK, but for CAD I have no idea.

>>  If it's RGB then some shade of red (or green or blue) is a good bet.  If

>> CMYK, use magenta.  It should be easy to try out.

>>

>> Printers will tell you that they lay down overlapping, microscopic

>> patterns of dots at various angles to each other (a bit like polarised

>> filters) to achieve various colour effects.  This may not work well with

>> 0.1 point lines.  If you need to mix two inks to get that line, my hunch is

>> it's more likely to mess up.

>>

>> Please let us know tomorrow!

>>

>> - Andy

>>

>> _______________________________________________

>> reportlab-users mailing list

>> reportlab-users at lists2.reportlab.com

>> http://two.pairlist.net/mailman/listinfo/reportlab-users

>>

>>

>

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