Problem with TppMemo's leading

rbuser

Hi,

I've encountered a bug with TppMemo's Leading property. We were getting a
"Division by zero" with the following callstack info.

[00E67C09] Ppviewr.TppScreenDevice.DrawStandardText
[40005F5B] System.@HandleAnyException

The problem comes from the following part of the DrawStandardText procedure.

procedure TppScreenDevice.DrawStandardText(aDrawText: TppDrawText);
[...]
begin
[...]

FCanvas.Font.Name :=
TppDeviceSubstitutions.SubstituteFont(aDrawText.Font.Name);

{set font height}
FCanvas.Font.Height := Round(aDrawText.Font.Height * FScaleY);

lbTruncTheText := False;

{font size must at least be one}
if (FCanvas.Font.Height = 0) then
FCanvas.Font.Height := -1;

[...]

GetTextMetrics(FCanvas.Handle, lTextMetric);

{get leading for this font}
if not(aDrawText.IsMemo) then
liLeading := lTextMetric.tmExternalLeading
else
liLeading := Trunc(ppFromMMThousandths(aDrawText.Leading,
utScreenPixels, pprtVertical, nil));

liLineHeight := lTextMetric.tmHeight + liLeading;

if (aDrawText.WrappedText.Count > 0) then
liCalcHeight := Round((lDrawRect.Bottom - lDrawRect.Top) /
aDrawText.WrappedText.Count)
else
liCalcHeight := 0;

if ((Abs(liCalcHeight - liLineHeight) / liLineHeight) <= 0.10) then
{!!!!!!!!!!!!Div by 0 here!!!!!!!!!!!!}
liLineHeight := liCalcHeight


[...]
end;


Here's what happens. aDrawText.Font.Name = 'Arial Narrow',
aDrawText.Font.Size = 8, aDrawText.Font.Height = -11, FScaleY =
0.14962121212

So, on line
FCanvas.Font.Height := Round(aDrawText.Font.Height * FScaleY);

FCanvas.Font.Height := Round(-11 * 0.14962....) //(Round(-1.64) = -2

Setting this sets the FCanvas.Font.Size to 2.

The call to
GetTextMetrics(FCanvas.Handle, lTextMetric);
Returns a value of lTextMetric.tmHeight of 2.

so

liLineHeight := lTextMetric.tmHeight + liLeading; //( liLineHeight =
0)

then on line
if ((Abs(liCalcHeight - liLineHeight) / liLineHeight) <= 0.10) then
{!!!!!!!!!!!!Div by 0 here!!!!!!!!!!!!}


If I use a Leading of -3 or -1 I don't have any problem. But -3 is a little
too much, and -1 is not enough...


Why is this happening?
Is it considered a bug?
if not, why, and what "rules" should I follow to avoid receiving this
error?
if yes, when could we expect it to be fixed?


Info:

Delphi 2006
ReportBuilder 10.03 Standard
OS : Windows 2k
Printer : InfoPrint 1130 with driver version 7.4

nardmoseley

Thanks for reporting this issue, it will be fixed for the next maintenance
(RB 10.04) which will be available soon.

--
Nard Moseley
Digital Metaphors
www.digital-metaphors.com