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Annotation goes off right side of chart
Posted: Thu Nov 20, 2014 12:08 am
by 10546565
In the attached demo, I have a couple chart tools--one a TColorLineTool that I place at a specific location on the X (bottom) axis, and a annotation tool that I try to place right over the line to note the lines purpose.
If the line appears on the right side of the chart, I try to position the annotation so that it shifts right as not to cut off the text in the annotation--I even add margin for this. Here is my code for it:
Code: Select all
procedure SetLeftPos(aMiddle: double; aAnnTool: TAnnotationTool);
const
H_MARGIN = 50;
var
lLeft: Integer;
lR: TRect;
lAnnWidth: Integer;
begin
if not aAnnTool.Active then
exit;
lLeft := aChart.BottomAxis.CalcXPosValue(aMiddle);
lR := aAnnTool.Bounds;
lAnnWidth := lR.Right- lR.Left + 1;
aAnnTool.Shape.Left := lLeft - (Max(0, lAnnWidth) div 2);
if aAnnTool.Shape.Left + aAnnTool.Shape.Width > (aChart.Width - H_MARGIN) then
aAnnTool.Shape.Left := aChart.Width - H_MARGIN - aAnnTool.Shape.Width;
aAnnTool.Shape.Top := 30;
end;
But this can still put the annotation too far right. See here:
I cannot figure out how to get this so it does not go off the right side of the chart. How can I achieve that?
A demo of this is attached.
Thank you,
Ed Dressel
Re: Annotation goes off right side of chart
Posted: Thu Nov 20, 2014 10:52 am
by yeray
Hi Ed,
It works fine using the TAnnotationTool Left property to reposition it instead of using the TAnnotationTool Shape.Left peoperty.
Ie:
Code: Select all
procedure SetLeftPos(aMiddle: double; aAnnTool: TAnnotationTool);
const
H_MARGIN = 25;
var
lLeft: Integer;
lR: TRect;
lAnnWidth: Integer;
begin
if not aAnnTool.Active then
exit;
lLeft := aChart.BottomAxis.CalcXPosValue(aMiddle);
lR := aAnnTool.Bounds;
lAnnWidth := lR.Right- lR.Left + 1;
aAnnTool.Left := lLeft - (Max(0, lAnnWidth) div 2);
if aAnnTool.Left + aAnnTool.Shape.Width > (aChart.Width - H_MARGIN) then
aAnnTool.Left := aChart.Width - H_MARGIN - aAnnTool.Shape.Width;
aAnnTool.Shape.Top := 30;
end;
Re: Annotation goes off right side of chart
Posted: Thu Nov 20, 2014 3:31 pm
by 10546565
Thank you for the quick response. This addressed part of my issue but I didn't realize there is another issue.
When rendering the chart to a graphic, if the graphic is a different size than the chart, I don't know how to get the right width of the chart.
In the attached example, I added a TImage that shows the chart but of a different size. The annotation is always in the wrong position.
How can I get this right?
Sincerely,
Ed Dressel
Re: Annotation goes off right side of chart
Posted: Fri Nov 21, 2014 11:49 am
by yeray
Hi Ed,
Debugging your application you'll see the SetLeftPos method (called at UpdateAnnotationPosition, called at Chart1BeforeDrawSeries) is executed both when the chart is being drawn on the form and when it's drawn on the bitmap.
The problem is that Chart1.Width at this line is always the same, it hasn't changed to take the width of the bitmap yet:
Code: Select all
if aAnnTool.Left + aAnnTool.Shape.Width > Chart1.Width then
To overcome this, I've made a slight trick.
I've created a global variable:
I initialize it to false:
Code: Select all
constructor TForm1.Create(aOwner: TComponent);
begin
inherited;
updatingImage:=false;
//...
I set it to true before exporting the bitmap and back to false after it:
Code: Select all
procedure TForm1.UpdateImage;
//...
begin
updatingImage:=true;
//...
AssignChartToGraphic(Chart1, lRect, lGraphic);
//...
updatingImage:=false;
end;
So now at SetLeftPos I can use the chart width or the Image width depending on where I'm coming from:
Code: Select all
procedure SetLeftPos(aMiddle: double; aAnnTool: TAnnotationTool);
var
//...
chartWidth: Integer;
//...
if updatingImage then
chartWidth:=imgChart.Width
else
chartWidth:=aChart.Width;
if aAnnTool.Left + aAnnTool.Shape.Width > chartWidth then
aAnnTool.Left := chartWidth - aAnnTool.Shape.Width;
//...