I am in need of creating a X,Y plot chart.
It seems that TGraph can only make time-series point and/or line charts, i.e. plot the value of Y and increment the X value by 1 unit for each data point of Y. Since there is no documentation for TGraph it is hard to tell if it is capable of X,Y charts.
Does anyone know? If so, do you have an example?
James
James,
In tgraph.prg we find:
so it seems as a point type is supported.
In order to select a type we have to do:
oGraph:nType := GRAPH_TYPE_POINT
oGraph:Refresh()
I have not tested it yet
@ 1, 1 GRAPH oGraph;
SIZE 250, 200;
TYPE 3; // GRAPH_TYPE_...
YVALUES 3D XGRID YGRID XVALUES LEGENDS
Antonio,
Yes, I have done that for years. But that is a Time-Series chart. You cannot specify the X value, only the Y value. So, X is always 1,2,3,4...and they are at equally spaced intervals. These are basically bar charts, using points and lines instead of bars.
I need to be able to plot user specified x and y points. E.G.:
X, Y
3.21,152
5.13, 133
7.67, 121
etc.
Does that clarify it?
There is another issue I forgot to mention. It seems that the Y-axis always starts at zero--there seems to be no way to specify the y-axis starting value. Thus, for instance, if you have a bunch of points all around 80 they are all going to appear very close together (almost in a straight line) since the Y-axis will be from 0 to 100. I need to be able to make the Y-axis start at around 70 and go to 100. I can't see a way to do this. I see what appears to be a hard-coded zero in the TGraph code for the start of the Y-axis.
James
James,
I am afraid that you need to review Class TGraph Method Paint() and implement your own painting method for a new type.
I am not familiar with Class TGraph source code, so you may need to review it and modify it to your needs.
Antonio,
Yes, that was my plan and I have done it before. But, before I start, I just wanted to check to make sure that x,y plots were not possible, and/or to see if anyone had already made any such modifications.
I was just looking at the code, and I forgot about another issue. It seems that the user defined X-axis label is printed on the Y-axis and visa versa. This makes it confusing when looking at the code since you don't know if it is just the label on the chart that is wrong, or are all the code vars containing a Y actually referring to the X-axis. This will be fun...
James
Hi James,
I know it is an old post, but did you implement X,Y plots in TGraph?
Thank you
Alvaro
Alvaro,
Sorry, no I never did. Most of my graphs are time series and TGraph works great for that. I can't remember what I did for the x,y plots that I needed back then, but I can find no evidence that I ever tried it. The TGraph code is quit complex and I expect it will take quite some time to modify it.
Regards,
James
James Bott wrote:Alvaro,
Sorry, no I never did. Most of my graphs are time series and TGraph works great for that. I can't remember what I did for the x,y plots that I needed back then, but I can find no evidence that I ever tried it. The TGraph code is quit complex and I expect it will take quite some time to modify it.
Regards,
James
#Define GRAPH_TYPE_XY_AQ 6
data chart_top
data chart_bottom
data chart_left
data chart_right
DATA nXMaxVal // Max Value
DATA nXMinVal // Min Value
data XY_Values METHOD aq_DrawLine( nY, nX, nHigh, nWidth, nColor, lDotted , nPenwidth )
METHOD aq_DrawPoint( nY, nX, nColor, lDotted , nPixels , nPenwidth )
// --------------------------------------------------------------------------- //
METHOD aq_DrawLine( nY1, nX1, nY2, nX2, nColor, lDotted , nPenwidth) CLASS TGraph
local x1,x2,y1,y2
local era_nPenwidth
default nPenwidth := 3
era_nPenwidth := ::nPenwidth
::nPenWidth := nPenwidth
x1 := ::chart_left + (nX1-::nXMinVal ) / (::nXMaxval-::nXMinVal) * ( ::chart_right - ::chart_left )
y1 := ::chart_bottom - (nY1-::nMinVal) / (::nMaxval-::nMinVal) * ( ::chart_bottom - ::chart_top )
x2 := ::chart_left + (nX2-::nXMinVal ) / (::nXMaxval-::nXMinVal) * ( ::chart_right - ::chart_left )
y2 := ::chart_bottom - (nY2-::nMinVal) / (::nMaxval-::nMinVal) * ( ::chart_bottom - ::chart_top )
::DrawLine( y1, x1, y2, x2, nColor, lDotted )
::nPenWidth := era_nPenwidth
return nil
// --------------------------------------------------------------------------- //
METHOD aq_DrawPoint( nY1, nX1, nColor, lDotted , npixels , nPenwidth ) CLASS TGraph
local x1,y1
local era_nPenwidth
default nPenwidth := nPenwidth
default nPixels := 7
era_nPenwidth := ::nPenwidth
::nPenWidth := 4
nPixels := nPixels /2
x1 := ::chart_left + (nX1-::nXMinVal ) / (::nXMaxval-::nXMinVal) * ( ::chart_right - ::chart_left )
y1 := ::chart_bottom - (nY1-::nMinVal) / (::nMaxval-::nMinVal) * ( ::chart_bottom - ::chart_top )
::DrawLine( y1 , x1-nPixels , y1+nPixels, x1, nColor, lDotted )
::DrawLine( y1+nPixels , x1 , y1, x1+nPixels, nColor, lDotted )
::DrawLine( y1 , x1+nPixels , y1-nPixels, x1, nColor, lDotted )
::DrawLine( y1-nPixels , x1 , y1 , x1-nPixels , nColor, lDotted )
::nPenWidth := era_nPenwidth
return nil ::XY_Values :={}::chart_top := nTop
::chart_bottom := nBottom
::chart_left := nLeft
::chart_right := nRight IF ::nType == GRAPH_TYPE_XY_AQ
FOR nJ := 1 TO Len( ::aSeries )
for nI := 1 to len( ::XY_Values[nJ] ) -1
::aq_Drawline( ::XY_Values[nJ, nI,2] , ::XY_Values[nJ,nI,1] , ;
::XY_Values[nJ, nI+1,2] , ::XY_Values[nJ, nI+1,1], ::aSeries[nj,2] )
next nI
if len( ::XY_Values[nJ] ) == 1
::aq_DrawPoint( ::XY_Values[nJ, 1,2] , ::XY_Values[nJ,1,1] , ::aSeries[nj,2] ,, )
endif
next nJ
if ::lYVal
::Say( 325 , 80 , "Hola" , ::aFont[3], rgb(0,0,0) , ::nTLeft )
endif
endif oChart:nType := GRAPH_TYPE_XY_AQ
oChart:nMaxVal := max_value // your calculated max value for Y axis
oChart:nMinVal := min_value // your calculated min value for Y axis
oChart:nXMaxVal := max_Xvalue // your calculated max value for X axis
oChart:nXMinVal := min_Xvalue // your calculated min value for X axis
oChart:AddSerie( {} , "name_or_the_serie1" , RGB(128,128,255) ) // empty array
aadd( oChart:XY_Values , aArray1 ) // aArray1 is an array with the XY points i.e. { { 1.25 , 9.25} , { 1.5 , 9.452 } , ......}
oChart:AddSerie( {} , "name_or_the_serie2" , RGB(128,128,255) ) // empty array
aadd( oChart:XY_Values , aArray2 ) // aArray2 is an array with the XY points i.e. { { 3.25 , 7.25} , { 2.5 , 8.452 } , ......}
you may add more seriesJames Bott wrote:Alvaro,
Wow, very impressive. May I get a copy of your new tgraph.prg?
You can find my email address on my website http://gointellitech.com.
Alvaro,
Would you mind to post it here or send it to me by email, so we can include it in next FWH 18.02 ?
many thanks
Alvaro,
It is not clear to me if you are automatically finding the min and max for each axis in the class, or if you must do the calculation outside the class and pass those values.
One of the first programs I wrote (way back in the BASIC era, circa 1980), I wrote code to find those values. I discovered that it was a challenge to find those values since they needed to be rounded up (or down) to a reasonable number that made the chart look right. E.G. rounding 10.3 to 11 or 15 or whatever.
Of course, being able to specify the ranges by overriding the internal calculations would also be useful.
May I suggest changing this line:
oChart:nType := GRAPH_TYPE_XY_AQ
To something like this:
oChart:nType := GRAPH_TYPE_XY //AQ
I am assuming AQ are your initials? The above change just keeps the naming consistent with the existing ones.
If you care to share this modified class with everyone, then I would also first make sure you have the latest copy of TGraph, and make your changes to that version. Also I would suggest adding comments at the top explaining your work and adding your name and contact info.
I am looking forward to seeing your modified TGraph class.
Regards,
James
James Bott wrote:Alvaro,
It is not clear to me if you are automatically finding the min and max for each axis in the class, or if you must do the calculation outside the class and pass those values.
One of the first programs I wrote (way back in the BASIC era, circa 1980), I wrote code to find those values. I discovered that it was a challenge to find those values since they needed to be rounded up (or down) to a reasonable number that made the chart look right. E.G. rounding 10.3 to 11 or 15 or whatever.
Of course, being able to specify the ranges by overriding the internal calculations would also be useful.
------------------------------
May I suggest changing this line:
oChart:nType := GRAPH_TYPE_XY_AQ
To something like this:
oChart:nType := GRAPH_TYPE_XY //AQ
I am assuming AQ are your initials? The above change just keeps the naming consistent with the existing ones.
If you care to share this modified class with everyone, then I would also first make sure you have the latest copy of TGraph, and make your changes to that version. Also I would suggest adding comments at the top explaining your work and adding your name and contact info.
I am looking forward to seeing your modified TGraph class.
Regards,
James
oChart:nXMaxVal := max_Xvalue + ( max_Xvalue - min_Xvalue ) *.1
oChart:nXMinVal := min_Xvalue - ( max_Xvalue - min_Xvalue ) *.1