Configuring QCAD for 3 Decimal Places in Metric System Floor Plans

Kmeelo · November 24, 2023, 11:20pm

Hello QCAD Community,

I’m a newcomer to QCAD, so please bear with me! I’m currently working on a floor plan, and I’ve noticed an abundance of decimals when incorporating area measurements into the drawing. Since I’m operating within the metric system, can anyone guide me on how to set QCAD to display only three decimal places after the point?

Kindly refer to the attached image for clarification.

I appreciate any help you can provide.

Husky · November 25, 2023, 2:26am

Hello,

you can set the global “Label Format” precision like “3 places after point” below:
Menu / Edit / Drawing Preferences / Dimension / Dimension Settings

CVH · November 25, 2023, 10:45am

Hi,

To my knowledge the number of decimal places of the info tools aren’t all governed by the drawing dimension settings.
And then the area of a polygon is an exception.

Polygonal Area (IR):
→ Area to 12 decimal digits but always as short as possible
→ There is no preference, setting nor option that has an influence.

We can look it up:
Polygonal Area (IR) = InfoArea.js

github.com/qcad/qcad

scripts/Information/InfoArea/InfoArea.js

master

/**
 * Copyright (c) 2011-2018 by Andrew Mustun. All rights reserved.
 * 
 * This file is part of the QCAD project.
 *
 * QCAD is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * QCAD is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with QCAD.
 */

include("scripts/Information/Information.js");

This file has been truncated. show original

Line 128 calls for a formatted area text string omitting a parameter:

github.com/qcad/qcad

scripts/Information/InfoArea/InfoArea.js

master


      
          };
          
          InfoArea.prototype.getOperation = function(preview) {
              if (isNull(this.polyline)) {
                  return undefined;
              }
          
              var di = this.getDocumentInterface();
              var op = new RAddObjectsOperation();
              op.setText(this.getToolTitle());
              this.addShape(op, this.polyline, preview);
          
              var view = di.getLastKnownViewWithFocus();
              view = getRGraphicsView(view);
              var areaText = this.getAreaText();
              view.clearTextLabels();
              var c = this.polyline.getLastVertex();
              if (c.isValid()) {
                  this.addTextLabel(op, view, c, areaText, preview);
              }

Line 138-140 calls a Information.js function for formatting a value with no rounding:

github.com/qcad/qcad

scripts/Information/InfoArea/InfoArea.js

master


      
          
              var view = di.getLastKnownViewWithFocus();
              view = getRGraphicsView(view);
              var areaText = this.getAreaText();
              view.clearTextLabels();
              var c = this.polyline.getLastVertex();
              if (c.isValid()) {
                  this.addTextLabel(op, view, c, areaText, preview);
              }
          
              return op;
          };
          
          InfoArea.prototype.getAreaText = function(rounded) {
              return this.formatAreaResult(this.getArea(), rounded);
          };
          
          InfoArea.prototype.getArea = function() {
              var pts = this.polyline.getVertices();
              var area = 0;
              var nPts = pts.length;

Line 81 of Information.js lines 75-96 sets precision = 12

github.com/qcad/qcad

scripts/Information/Information.js

master


      
              if (isNull(this.doc)) {
                  return "";
              }
          
              return this.doc.formatAngle(angle);
          };
          
          Information.prototype.formatAreaResult = function(area, rounded) {
              if (isNull(this.doc)) {
                  return "";
              }
          
              var prec = 12;
              if (rounded) {
                  prec = 3;
              }
          
              var areaText;
              if (this.doc.getUnit()===RS.Inch) {
                  var sqft = Math.floor(area/144);
                  var sqin = area-sqft*144;

This value is left unchanged there variable ‘rounded’ is undefined. Rounded it would be 3 decimal digits.
With a drawing unit other than ‘Inch’ the area string is then constructed by RUnit.cpp with leading, without trailing zeros

github.com/qcad/qcad

scripts/Information/Information.js

master


      
              var prec = 12;
              if (rounded) {
                  prec = 3;
              }
          
              var areaText;
              if (this.doc.getUnit()===RS.Inch) {
                  var sqft = Math.floor(area/144);
                  var sqin = area-sqft*144;
                  return "%1 (= %2ft² %3in²)".arg(area).arg(parseFloat(sqft.toFixed(prec))).arg(parseFloat(sqin.toFixed(prec)));
              }
              else {
                  return RUnit.doubleToStringDec(parseFloat(area), prec, true, false, this.doc.getDecimalSeparator());
                  //return "%1".arg(area, 0, 'f', prec);
              }
          };
          
          /**
           * \return Result formatted in dimension label format and with 6 decimal points.
           * e.g.: "3 1/3 [3.333333]"
           */

github.com/qcad/qcad

src/core/RUnit.cpp

master


      
          * Converts a double into a string which is as short as possible.
          *
          * @param value The double value
          * @param prec Precision
          */
          QString RUnit::doubleToString(double value, int prec,
                 bool /*showLeadingZeroes*/, bool showTrailingZeroes,
                 char decimalSeparator) {
          
             QString ret;
          
             QString formatString;
             if (showTrailingZeroes) {
                 formatString = QString("%.0%1f").arg(prec);
             }
             else {
                 formatString = QString("%.%1f").arg(prec);
             }
          
             // avoid banker's rounding, always round 0.5 up and -0.5 down:

This file has been truncated. show original

In Line 873-877 we see that it is handled differently for Qt6

If after all this you expect 12 decimal digits (not Qt6) then you are in for a surprise … It has definitely changed since for example 3.27.6
One can verify the area value with Misc .. Information .. 2D Centroids .. Area Centroid.
After creation see the custom properties of the Centroid marker, reported values are as exact as can be in full floating point notation.
Centroids code exploits specialized algorithms to avoid known pitfalls in floating point arithmetic.

The Info tools also report a user information on the Command Line History and that might be in a different and/or mixed format.
Between brackets up to 6 decimal digits, so-called ‘Exact’, and only if different string-wise with the formatted string for the Command Line.

For IP - IE - IN there is a hidden preference in the QCAD.ini/config that I exploit to get full floating point information:
[Info] Precision=17 (The number of decimal digits, -1 = normal)
Not to be confused with number precision what is the amount of significant digits.
Quite important at GUI level when creating custom scripts handling all kinds of geometric information.

Remark that the option ‘Add measurement to drawing’ may also add other entities to the drawing than only measurements as text:
→ A point, lines and ticks (= more lines), an arc, a polygon, plain entity copies, a chord (or 2 radii).
And that this is not configurable except for IC.

Regards,
CVH

Kmeelo · November 26, 2023, 11:41am

It didn’t work see attached.

CVH · November 26, 2023, 3:07pm

As explained, no.
You might want to file a bug report or a feature request here: Flyspray::QCAD Bugtracker: Tasklist
For that you need a separate account or create a new one.

The work around is obvious, edit the text, truncate or round the value.

Regards,
CVH

Kmeelo · November 26, 2023, 5:10pm

I will file a report. Thank you so much for your help!