mORMot Open Source

Hi.
I'm trying to use TTaskDialog with custom width (auto width is not suitable for me) and aNonNative=False.
Test code is:

  Task.Inst := 'Content';
  Task.Buttons := 'Button1'#13'Button2';
  Task.Execute([],100,[tdfUseCommandLinks],tiWarning,tfiInformation, 0, 480);

When I use it under windows XP it works well, but under Windows 7 message window width is getting too big.
I think the reason is that when you emulate (under Windows XP) the Width parameter indicates the width of the window in pixels, but when using TaskDialogIndirect cxWidth is in Dialog Units (accoding to documentation).

Thank you

You believe that a reference value for computing floating point is a string. I think that the number (binary representation) is more important. Let me explain my position. I plan to store in the database a set of coordinates in JSON format. Initially the coordinates are numbers ("Single" type). The user should be able to change the coordinates of individual points, leaving the rest unchanged. As a result of coordinate will periodically be converted from JSON (text) to numeric form and Vice versa. I am afraid that as a result of errors discussed above after multiple conversions coordinates will started to "drift" each time the user edits the data.
With increased accuracy data can be easy converted multiple times without loss of information.

I tried the latest version of "SynCommons.pas" from http://synopse.info/fossil/info/846978294b
The behaviour with "Single" and "Double" types is improved.
Unfortunately, with new version of "SynCommons.pas" the following code starts to cause error "Invalid pointer operation":

var
  v1, obj: Variant;
begin
  v1 := _Arr([]);
  obj := _Obj(['id', 1]);
  v1.Add(obj);
  caption := VariantSaveJSON(v1);
end;

Also after error FastMM4 reports that memory leak appears.
Previous versions of "SynCommons.pas" have no problems with such code.

Think you very much. The new version do exact what I want with variables of "Single" type.

Sorry for molestation. But I think you would resolve the error, about which I wrote above. It still alive. The following code:

var
  s: Double;
  v1: Variant;
begin
  v1 := _Arr([]);
  s := 1.23456;
  v1.Add(s);
  caption := VariantSaveJSON(v1);
end;

cause an error "TTextWriter.AddVariantJSON(VType=16389)" when variable "s" has type "Single" or "Double". Only declaration "s: Extended" cause no error. I think this is a serious error. Few people use the type "Single". But the type "Double" is very popular (I think it is more popular than "Extended" as for the reason of compatibility with "double" from "C" language and for the reason that its length is a multiple of 8 bytes, which is beneficial to program performance.

I can give an example of task when I want to use "single" precision. I am writing an application to handle geodata. End-point devices use GPS-receivers to determine their location. Then they send data to server using GSM channel. My application requests data from the server and shows objects on a map.
GPS receivers send their data using NMEA format. This format uses only 8-9 significant digits to represent latitude and longitude. So "single" type was chosen for storing coordinates.
Client application communicate with the server using JSON format. And I see that when server sends coordinates It uses significantly more digits than necessary. I the future when number of end-point devices grows JSON message will have large extra length and lead to excessive internet traffic.
I looked at the source "SynCommons.pas" and found that the code provides for the possibility to use a "Single" (for example, declared and used constant "SINGLE_PRECISION"), but did not understand how to use this feature. I have tried several ways but got the same result.