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TAChart: Correctly calculate TFuncSeries.GetNearestPoint

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git-svn-id: trunk@32075 -
This commit is contained in:
ask 2011-08-28 06:18:35 +00:00
parent dd9ce14656
commit 64c42d5290
1 changed files with 73 additions and 14 deletions
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87
components/tachart/tafuncseries.pas
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@ -273,6 +273,9 @@ type
ADrawer: IChartDrawer; ASeries: TCustomChartSeries;
ADomainExclusions: TIntervalList; ACalc: TTransformFunc; AStep: Integer);
procedure DrawFunction;
function GetNearestPoint(
const AParams: TNearestPointParams;
out AResults: TNearestPointResults): Boolean;
end;
function DoublePointRotated(AX, AY: Double): TDoublePoint;
@ -355,6 +358,68 @@ begin
end;
end;
function TDrawFuncHelper.GetNearestPoint(
const AParams: TNearestPointParams;
out AResults: TNearestPointResults): Boolean;
procedure CheckPoint(AXg, AXa: Double);
var
inExtent: Boolean;
gp: TDoublePoint;
ip: TPoint;
d: Integer;
begin
CalcAt(AXg, AXa, gp, inExtent);
if not inExtent then exit;
ip := FChart.GraphToImage(gp);
d := AParams.FDistFunc(AParams.FPoint, ip);
if (d >= AResults.FDist) or (d > Sqr(AParams.FRadius)) then exit;
AResults.FDist := d;
AResults.FImg := ip;
AResults.FValue.X := AXa;
Result := true;
end;
var
hint: Integer;
xg, xa, xg1, xa1, xmax: Double;
begin
AResults.FIndex := -1;
AResults.FDist := MaxInt;
Result := false;
with AParams do
if FSeries.IsRotated then begin
xg := Max(FExtent.a.Y, FChart.YImageToGraph(FPoint.Y - FRadius));
xmax := Min(FExtent.b.Y, FChart.YImageToGraph(FPoint.Y + FRadius));
end
else begin
xg := Max(FExtent.a.X, FChart.XImageToGraph(FPoint.X - FRadius));
xmax := Min(FExtent.b.X, FChart.XImageToGraph(FPoint.X + FRadius));
end;
hint := 0;
xa := FGraphToAxisXr(xg);
if FDomainExclusions.Intersect(xa, xa, hint) then
xg := FAxisToGraphXr(xa);
CheckPoint(xg, xa);
while xg < xmax do begin
xg1 := xg + FGraphStep;
xa1 := FGraphToAxisXr(xg1);
if FDomainExclusions.Intersect(xa, xa1, hint) then begin
CheckPoint(FAxisToGraphXr(xa), xa);
xg1 := FAxisToGraphXr(xa1);
CheckPoint(xg1, xa1);
end
else
CheckPoint(xg1, xa1);
xg := xg1;
xa := xa1;
end;
end;
procedure TDrawFuncHelper.LineTo(AXg, AXa: Double);
var
p, t: TDoublePoint;
@ -492,23 +557,17 @@ end;
function TFuncSeries.GetNearestPoint(
const AParams: TNearestPointParams;
out AResults: TNearestPointResults): Boolean;
var
t: Double;
dummy: Integer = 0;
begin
Result := false;
AResults.FIndex := -1;
if OnCalculate = nil then exit;
// Instead of true nearest point, just calculate the function at the cursor.
with GraphToAxis(ParentChart.ImageToGraph(AParams.FPoint)) do begin
t := X;
if DomainExclusions.Intersect(t, t, dummy) then exit;
AResults.FValue.X := X;
end;
OnCalculate(AResults.FValue.X, AResults.FValue.Y);
AResults.FImg := ParentChart.GraphToImage(AxisToGraph(AResults.FValue));
AResults.FDist := AParams.FDistFunc(AParams.FPoint, AResults.FImg);
Result := AResults.FDist <= Sqr(AParams.FRadius);
if not Assigned(OnCalculate) then exit;
with TDrawFuncHelper.Create(nil, Self, DomainExclusions, @DoCalculate, Step) do
try
Result := GetNearestPoint(AParams, AResults);
finally
Free;
end;
end;
function TFuncSeries.IsEmpty: Boolean;