backcolor subdivision
lazarus / 55-TAChart

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frederic · 2016-03-22 20:57

dear specialists

when one defines the backcolor of a chart the whole chart area is
meant.

i wondered ,if it is possible to subdivide the canvas of the chart in
different backcolors colors  in stead of one color

f.i.       0<x10 , 0<y<100: clyellow
           10<x <50,0<y<100 :clblue
          50<x<100,0<y<100: slsilver

frederic

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wp · 2016-03-22 22:34

Add a TChartStyles component, select the component, in the object
inspector click at the "..." next to "styles", add two styles, set
their color by using their brush. Then assign the TChartStyles to the
Strips of the BottomAxis.Marks. See attached demo.

If you want irregular intervals you have to add (another) axis to
which you assign the styles.

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frederic · 2016-03-23 11:24

wp,

i tried with the styles property , but it is meant for a repetitive
performance.

i tried to make it simple
target:
on a bottomscale of 0 to 200  i want to able to have the area  0-150
in clblue and beyond to 200 in clyellow
the xvalue of 150 must be adjustable

when i fill  with styles1 (chartstyle1=clbleu and chartsstyle2
=yellow) :repeatcount = 150  then the whole area turns bleu  instaed
of what i would expect 150-200 in yellow


how i should use a second bottomaxis is not clear to me

frederic

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wp · 2016-03-23 14:56

See attached project.

Yes, the TChartStyles are mean for repetitive action. So, you must
prevent it to become repetitive, you must cover the entire axis space
by stripes, they only repeat themselves if any axis extent it left.

Add a TListChartSource, it will define the points where the color
changes. In your example, it is only one, 150. Add code to write this
number into the listchartsource, only this more, no more!

Then add a second x axis (ObjectTree, right-click "AxisList" --> "Add
item"). Select the new axis, it is a y axis by default, but by setting
"Alignment" to alBottom it becomes an x axis. Select both x axes, set
their "Group" to any non-zero number (e.g. 1), this causes both x axes
to be drawn on the same line. Select Marks of the new x axis, hide the
labels by setting "Visible" = false. Set "Source" to the
ListChartSource added above. Set "Stripes" to the TChartStyles. You
need two stripes, the first one blue, the second one yellow. The first
stripe reaches from "neg inifinity" up to the point defined in the
list chource, the second one from this point up to "pos infinity".

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frederic · 2016-03-23 15:51

wp,
 interesting ,that gives me a kick in the right direction
never thought of using a separate listchartsource  for that .

that gives indeed great flexibilty better than in delphi

thanks

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frederic · 2016-03-24 10:51

wp

i need to set the colors of the stripes by code .

how do you do that?

thanks for the hint ,in advance
frederic

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wp · 2016-03-24 11:04

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  
ChartStyles1.Styles[0].Brush.Color := Color1; 
ChartStyles1.Styles[1].Brush.Color := Color2;  Chart1.Invalidate;

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frederic · 2016-03-31 08:48

little question

when i want to delete an object from the chart i click on the icon on
the chart and delete.
when i do this with the chartstyles icon ,i get acces violation

why is that?

frederic

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wp · 2016-03-31 09:40

Seems to be a bug. Let me see...

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wp · 2016-03-31 10:03

Should be fixed in r52090. Please test and report back.

If you don't use Lazarus trunk you can probably apply this temporary
patch manually to older versions:
Go to folder (lazarus)/components/tachartMake a backup copy of
TAGraph.pasOpen TAGraph.pas in Lazarus or any other editorFind the
"uses" line after "implementation", add "TAStyles"Find the procedure
"TChart.Notification", replace it by the following code. Then rebuild
the IDE.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 procedure
TChart.Notification(AComponent: TComponent; AOperation:
TOperation);var  ax: TChartAxis;begin  if (AOperation = opRemove) and
(AComponent = Toolset) then    FToolset := nil  else if (AOperation =
opRemove) and (AComponent = GUIConnector) then    GUIConnector := nil 
else if (AOperation = opRemove) and (AComponent is TChartStyles) then
begin  // <-- added from here ...    for ax in FAxisList do      if
ax.Marks.Stripes = AComponent then        ax.Marks.Stripes := nil; 
end;                                                                 
      // <-- ... to here   inherited Notification(AComponent,
AOperation);end;

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frederic · 2016-03-31 11:20

i use now 1.6 svn 51630    2016-2-14;
i will update my version first

frederic

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frederic · 2016-03-31 12:41

i used the latest official lazarus release,

i changed the code in the notification procedure and ran your project
from above,
i got an error that the class tastyles was missing before i even
deleted it.

i may have done something else wronge due to my unexperience , ( i
never changed lazarus code before ,one bridge to far). so i leave 
this item here

frederic

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wp · 2016-03-31 15:36

Before you compile any chart project you MUST rebuild the IDE because
you want to delete the ChartStyles in designmode, and the new code
must be contained in the IDE. The easiest way to recompile Lazarus is
to open the menu "Tools" and select "Build Lazarus with profile...".
The compilation process takes some time, be patient. At the end
Lazarus closes and restarts automatically with the new IDE. Then you
can begin with a new project, add a TChart and TChartStyles, and link
the ChartStyles to the Marks.Stripes of one of the axes. If you now
delete the TChartStyles from the IDE it must not crash any more.

If the compilation of Lazarus fails or the newly started Lazarus hangs
you have a backup of the old lazarus.exe named as lazarus.old.exe -
rename it to lazarus.exe and your can use the old Lazarus again.

I tested the patching and recompilation procedure with a new
installation of Laz 1.6 - it works, for sure.

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frederic · 2016-03-31 19:22

oke , wp ,  it works

frederic

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wp · 2016-03-31 19:33

I put it onto the merge list for Lazarus 1.6.2. So, when the new
version will be released and you update you will have the fix
included.