Graph Software for Scientists and Engineers

Revision History

Licensed users should sign up for the mailing list to receive instructions for downloading the free upgrade, or select Check for Updates on the Help menu within DPlot.

Green entries are programming issues, generally concerning DPLOTLIB.DLL and/or the Excel Add-In.

10 Feb 2017

  • Bug fix: Gave up on trying to verify DPlot's own digital signature with new, more secure sha256 algorithm. Attempting to verify the signature under both Windows Vista and Windows XP resulted in errors that erroneously indicated the file had been tampered with.

31 Jan 2017

  • Fixed a problem that only affected Windows XP users. If you have and are not running XP, there is no reason to update. The problem was related to updating to a more secure code-signing algorithm used by DPlot (which is not supported by XP).

27 Jan 2017

  • Added setting for FileNew and FileNewEx commands to create an empty 3D scatter plot.
  • The DPlot Add-in is now signed by an established certificate authority, which gets around a few Excel Trust Center settings. For more information see the blog entry on the subject.
  • DPlot might have crashed (or at the very least presented nonsense values) when opening file type N (unformatted binary, 64 bit). The problem was due to mistakenly identifying the file as 32-bit binary.
  • Improved the accuracy of the NUMDISTCDF and ERF functions (used by Y=f(X) and similar commands) for X < -5.
  • Improved saving metafiles of 2D contour plots with "Data points" checked on the Contour Options dialog. In previous versions the symbols were drawn point-by-point. This was fine for bitmaps, printouts, and displays, but resulted in very large metafiles because of the "resolution" of 2540 dpi.
  • Bug fix: An error in the Operate on X command might have resulted in a syntax error on something as simple as "x+1"
  • Bug fix: The $RMS text placeholder sometimes did not work correctly for 3D data on a rectangular grid.
  • Bug fix: Limits on frequencies in the Filter command were incorrect for all time units other than seconds.
  • Bug fix: If you used the Reorder Curves command on a bar chart with multiple data sets, the fill styles were not shifted along with the corresponding bar(s).
  • Bug fix: The specified font color for the legend in 3D plots was ignored and was always black.
  • Bug fix: If you attempted to use the Differentiate a Curve command on a plot that had no curves with monotonically increasing X values, DPlot correctly refused to perform the command, but didn't clean up properly and broke subsequent attempts to run most commands that displayed a list of curves.
  • Text notation button text is now saved to and restored from preference files.
  • Added "Select all" and "Deselect all" options to the Combine Curves command.
  • Bug fix: The Y=f(X,Y1,Y2,...) command might have resulted in a file being erroneously saved with a flag indicating that the X values had a constant spacing.
  • Bug fix: The frequency setting for Error bars was ignored for bar charts.
  • Bug fix: Reference line values entered with Time of day (fractional days) number format for the associated axis were interpreted incorrectly. Internally the value was treated as whole number hours rather than fractions of a day.
  • Bug fix: The "Sort on X" option of the Combine Curves command did not work properly in recent versions if you checked the "Keep originals" box.
  • The DPLOTLIB demo program did not compile correctly with recent versions of the Absoft FORTRAN compiler because of using the same name for the DPLOT structure as the DPlot record.
  • Bug fix: Exported images with embedded images were arbitrarily increased in size by 50% in an effort to ensure that the embedded images were not clipped (if, for example, placed along one of the sides of the graph. The downside to this change is that clipping may now occur, and this may require another change.

3 May, 2014

  • Bug fix: Reading 4-byte unformatted data was broken with the addition of support for 8-byte unformatted data in version
  • The Label Points command had a few quirks when working with hidden curves.
  • Bug fix: List Peaks did not report the correct mean or number of points for "curves" consisting of a single point.

17 March, 2014

  • DPlot will now correctly interpret text files with lines terminated by a carriage return only, as opposed to what most Windows users are accustomed to with a carriage return/line feed sequence.
  • Added a "Date separator" entry to the General Options dialog. This entry might be important for German users (or for users from any other country where the default date separator is a '.') who typically read text files in which the decimal point character is a '.'. (Version added support for '.' as the date separator, but this broke DPlot for many German users who also used '.' as the decimal point.)
  • DPlot is a bit smarter about re-allocating arrays for unformatted data, both 4- and 8-byte files. In previous versions when it was found that the arrays were of insufficient size, DPlot used the power of 2 greater than or equal to the required size. Since the required size was known, in many cases this was overkill - particularly for millions of points. In this version DPlot will size the arrays to the exact size needed. In many cases this will make the difference in whether DPlot can successfully read the file or not. Another change fixes a bug that under some circumstances might have led to a complaint about being unable to allocate memory for 100 curves, though the file contained only one data set.
  • Bug fix: The filter coefficients for the relatively new CFCx filters were fouled up, particularly D1 and D2.
  • Bug fix: Strangely, this bug has been present from day 1 but it is only recently that anybody has noticed it. In previous versions of DPlot, when printing if you specified more than 1 copy you'd actually get the square of that number rather than the specified number. The problem was that DPlot was looping through that number of copies, and for each loop the printer driver was also printing that number of copies.

22 February, 2014

  • The Playback feature now uses more modern settings for the Open dialog for videos. This should have been done years ago. Whoops!
  • Added a new file type that can be opened/saved. Unformatted binary (64-bit) is identical to the "Unformatted binary" type except that it saves data to 64-bit (8-byte) double-precision floating point values rather than 4-byte single-precision values. This might be important if you are working with large magnitude numbers with a small increment between points (date/time groups, for example) or if you have a large number of points (100,000 or so) and it is important that you preserve the increment between points.
  • Bug fix: Curve labels for plots using the Amplitude Limits feature might not have been aligned properly.
  • Bug fix: Version included a change that caused contour lines to not be drawn if the corresponding line width was set to less than 0. This worked, but line widths resulting in a calculated pen width of 1 pixel (on most systems 0.02") were also not drawn if antialiasing was turned on.
  • Bug fix: Blank cells in the Z (3rd) column exported to DPlot via the XYZSurface Add-In command were treated as 0's, rather than properly being ignored.
  • Bug fix: Since Version the default save folder might not have been preserved, depending on how a plot was created. The intent is to offer the last folder saved to as the default, which this version and those prior to do.
  • Amended the FileSaveAs command to accept multiple |TITLEn| placeholders.
  • The Pacific EU file import plugin will now accept an options string when used with the FileOpen macro/DDE command.
  • When using the Zoom toolbar button or when zooming by dragging-and-clicking (assuming "Click and drag to zoom" under the General Options command is checked), you can restrict zooming to the X direction by pressing the Ctrl key or to the Y direction by pressing the Shift key. Whether using the toolbar button or clicking-and-dragging, the key must be pressed and held before the action is initiated. NOTE: This change necessitated a change in restricting the zoom rectangle to a square. This is now accomplished by pressing and holding the ALT key (previously SHIFT key).
  • The DeferMinMaxCheck command now applies to data sent to DPlot with XY, XYXY, and/or XYZ commands. Previously this command only affected data sent via calls to DPlot_AddData.
  • Added "Vertical Grid Lines Only" and "Horizontal Grid Lines Only" menu commands to DPlot Jr. This omission was an oversight. Programmatically, you've always been able to control this setting with an AxisType command.

16 December, 2013

  • Version was amended to accept multiple arguments (curve indices). Unfortunately this change broke SelectCurve(-1), which previously meant that all curves should be selected for subsequent operations. SelectCurve(-1) works as expected in this release.

8 December, 2013

  • Added optional "Average Duplicate X's" and "Peak Y Values with Duplicate X's" for the Generate menu to the distribution for the licensed version of DPlot. For those users who have previously used these modules, both now allow you to select which curve to operate on as well as specify whether the generated data should replace the input.
  • Changed the SelectCurve macro/DDE command to accept multiple arguments (curve indices). In addition, the equivalent macro/DDE commands for all Edit menu commands that interactively allow you to select multiple curves now use this setting. So, for example,


    can now be replaced with



  • For 2D views of surface plots, if you set the major or minor contour line width values to less than 0, then the corresponding lines are not drawn. In previous versions those lines were drawn with a width of 1 pixel/printer dot.
  • Added ListPeaksOptions macro/DDE command.
  • Modified the Polynomial Curve Fit procedure to show dates/times if the number format for the X axis was a date and/or time. In previous versions the limits on the generated points were always shown as numbers, so a lack of precision might have resulted in the output extents being several seconds before or after the input extents.
  • Modified the $MEAN text placeholder to accept X limits in the same way that $YMIN and others work. For example $MEAN(2,20,50) returns the mean amplitude for curve 2 between X=20 and X=50 (inclusive). This change only applies to XY plots.
  • DPlot now uses version 3.15.4 of the FreeImage image library.
  • Bug fix: The List Peaks within a Range command on random 3D points might have crashed on some versions of Windows due to an uninitialized data problem.
  • Bug fix: Version included a fix to eliminate excess white space for curve labels that overlapped a plot border. In some cases this "fix" might have caused DPlot to crash.
  • Bug fix: "Fixed" a problem with the Excel Add-In for 64-bit Excel 2013 (and subsequent versions). The code that removed the DPlot Add-In menu when you removed the Add-In might have caused runtime errors in that version of Excel. The down side to this change is that the DPlot menu will remain after removing the Add-In and until you restart that version of Excel.
  • Bug fix: The function parser (used by Y=f(X) and similar commands, as well as in text placeholders that used an equation) did not properly handle numbers with an exponent. For example LOG10(5.3E-7) balked because of the minus sign.

14 July, 2013

  • Added right-click menu options to the legend of XY plots to snap the legend to one of a graph's four corners. See Anchor point>Snap to...
  • Added a Replace button (random 3D points) and Paste Z button (points on a rectangular grid) to the Edit Data dialogs of all 3D plot types. For random points this will replace the current data (X, Y, and Z values) with the clipboard contents. For points on a rectangular grid this will replace Z values with the clipboard contents, preserving X and Y. This might be handy if you frequently produce 3D surface or scatter plots with complicated setups: embedded images, long text notations, etc.
  • Bug fix: DPlot crashed when saving DPlot files with notes longer than 1024 characters.
  • Bug fix: For large framed notes the rectangle surrounding the note might have been a bit too small or too large for vertical text.
  • Bug fix: The Distance between points function for 3D surface plots with random points did not handle dragging the mouse to select points correctly.
  • Bug fix: There was a problem when reallocating arrays for XY plots with existing curves. If there was insufficient memory for the new array sizes, the old arrays might not have been restored and all values were set to 0's. And another: if in the same situation you attempted to allocate arrays such that the total number of points exceeded 2^32/8 (bytes per X or Y), DPlot might have crashed without warning.
  • Bug fix: There was a goof in the new Spline Fit dialog that caused the plugin to always operate on either the first or second curves, regardless of what selection you made in the plugin's dialog box.
  • Bug fix: Fixed a problem that has always existed for Generate plugins but only became noticeable with the last release's inclusion of the Spline Fit plugin: If you set the "Number of points per segment" to a value large enough that DPlot could not allocate enough memory to accomodate that new curve (e.g. 100 million or more points), the registry entry set by the plugin indicating inadequate array sizes was not reset. The result of this was that subsequent calls to that plugin would bypass the dialog box where you entered "Number of points per segment", because the plugin thought this was a subsequent call after successfully reallocating arrays.

21 June, 2013

  • Added MIN and MAX operations to the Z=f(Z1,Z2) menu command.
  • Added a Spline Fit function to the Generate menu. This operates in much the same way the Equal Intervals command with the Cubic Spline method does, but allows for input that loops back in X - is not a function, in other words. Thanks to Erik Larson for the code.
  • Added an option to the Histogram command to plot the frequency of a given bin rather than the count.
  • Added AND, NOT, OR, and XOR functions for use in Y=f(X), Operate on Y, and similar commands.
  • Bug fix: Text and arrows for point labels that were copied to the clipboard may have been incorrectly placed with standard (as opposed to enhanced) metafiles.
  • Bug fix: A roundoff error in axis label placement for 2D surface plots might have resulted in the last label being omitted.
  • Bug fix: With the XYYY Excel Add-In command, if you only selected one data column (correctly interpreted as Y, with X starting at 0 and incremented by 1.) and that column included a heading, the Add-In skipped over the first data point.

17 May, 2013

  • Added ability to make more than 2 passes with the Filter command. This might be useful for very noisy data.
  • Added candlestick chart option to Open-High-Low-Close (OHLC) charts.
  • Added a "Number of points" option to the "List Peaks" function.
  • Bug fix: The recent ATAN2 option for the Z3=f(Z1,Z2) command worked correctly for points on a rectangular grid, but not at all for randomly-spaced points.
  • Bug fix: Curve labels might had added uneccessary white space to the right side of a plot.
  • Bug fix: With 2D views of contour plots of randomly-spaced 3D points, the legend might have been clipped in a copied bitmap produced by Copy Picture.
  • Bug fix: The "More Curve Fits" function might have crashed with some equation forms if you selected a curve to fit that contained a single data point. In this release those "curves" are not selectable.
  • Bug fix: Since version there has been a rather obscure bug when using any of the Generate menu commands that result in a new document (FFT or Histogram, for example). If the original document contained any notes and you performed any operation on the generated document's data, then the Undo function did not work properly. Generally on a Redo all X and Y values were set to 0's.
  • Bug fix: DPlot crashed when zooming in, then out, with the mouse wheel while pressing the CTRL key (restricting zooming to the X direction) if the plot included multiple Y axes.
  • Expanded the FORTRAN DPLOTLIB examples to perform many more functions. Currently this has been done for WATCOM, g77, and Silverfrost (formerly Salford) examples. Others may follow in a future release. (If you use Absoft or Compaq/Intel FORTRAN, please contact me.)
  • The ZGrid command of the Excel Add-In is now much more efficient when you simply select column headings rather than the rectangle containing your data. And it now will correctly interpret evenly-spaced Y values when you select column headings and send the data to DPlot as points on a rectangular grid, rather than randomly-spaced points. This is important if your goal is to produce 3D bar charts.

17 March 2013

  • Added Open-High-Low-Close (OHLC) chart option. This is primarily useful for those tracking stock prices.
  • Added X=f(T), Y=g(T), Z=h(T) command on the Generate menu, which allows you to generate points in a 3D scatter plot with X, Y, and Z all a user-defined function of a fourth independent parameter T.
  • Added entries for the SAE J211 CFC filters to the Filter command on the Edit menu. This is mostly a matter of convenience to those who crash cars for a living: the filter coefficents are defined here.
  • Modified the MultipleXAxes and MultipleYAxes commands so that they will accept an equation as input.
  • Extents for scales using "Calendar Date" number formatting are now rounded to the nearest integer (nearest day). Though technically correct before, previous versions were visually confusing if, for example, the low extent was at some time other than midnight since the time was not shown.
  • The setup program now copies examples.xls to the DPlot folder below your "My Documents" folder.
  • Bug fix: Previous versions of the Excel Add-In for DPlot might have caused 64-bit Excel 2013 to crash (after successfully creating a plot).
  • Bug fix: Changing colors in an XY plot (with no other changes) did not result in prompting you to save the plot when it was closed.
  • Bug fix: If you erased a hidden curve, the hidden flag was not reset. If you then performed some operation that created a new curve (which filled the slot occupied by the previously erased curve), the new curve was hidden.
  • Bug fix: The plugin examples contained the wrong header file DPLOT.H.

25 January 2013

  • Updated the Garmin GPX file import plugin to import heartrate information stored between <gpxtpx:hr> tags. This includes Nike+ files exported as GPX and possibly other devices. If you have a GPS device that records heartrate and exports to GPX but heartrate is not supported by this plugin, of course let us know.
  • Added AxisArrowheads macro/DDE command.
  • Added ATAN2 operator to the Z3=f(Z1,Z2) command on the Generate menu for 3D surfaces.
  • DPlot files opened by double-clicking in Explorer or dragging-and-dropping on to the DPlot window now reset the default folder for opening files in the same way that the File>Open menu command works. In particular this might make a difference for you when using the Directory(1) macro command.
  • Bug fix: A SelectCurve command prior to an EditSmooth command did nothing. Generally every curve on the plot would be smoothed.
  • Bug fix: Version's change allowing you to print multiple plots with the placement determined by the order the plots were selected in was not implemented correctly, making it difficult to deselect the last plot that was selected.
  • Bug fix: In all previous versions if you used a text placeholder for a parameter in a macro command, e.g. [ManualScale(=$(XMIN),...], then the equation was replaced by a character string representation of the number with no more than 7 significant figures (identically to how the default number format works on the coordinate axes). In most cases this was fine, but didn't work so well in the case of date/time groups. For example 1 October 2012 9:00 PM was evaluated as 41183.88 (9:07:12 PM) rather than the exact 41183.875. In this release up to 16 significant figures are used in this situation.
  • Bug fix: DPlot crashed if every point in one or more curves was outside the limits set with the Amplitude Limits menu command.
  • Bug fix: 2D views of surface plots were not printed correctly if either the X or Y scale factors were negative.

25 September 2012

  • Bug fix: On an XY plot if minor grid lines were used on the Y axis and the minor grid lines used a different color than the major grid lines, DPlot would redraw the major grid lines on the X axis so that they would not be obscured by the minor Y lines. This worked fine unless the X axis used one of the calendar date formats. In that case the major lines were redrawn at a fixed interval, e.g. 30 days instead of one month. This bug has been present for over a year but only recently discovered by user PaulT. Thanks, Paul.
  • Minor change to reading DPlot files: "Print Caption" is turned off by default and only turned on if the file contains an instruction to do so. This differs from previous versions that tended to use the setting from the last plot that was opened.
  • One user reported a problem with the self-extracting zip file for the DPLOTLIB files that was used for the first time in the version This release doesn't use a zip file.

23 September 2012

  • The distribution now includes a 64-bit version of DPLOTLIB.DLL and 64-bit source code examples in C, C#, and VB.NET.
  • If a note that is automatically generated for a vector plot with the "Show color key" option is removed on the Note dialog, "Show color key" is turned off. In the last release the note would be regenerated with default options every time you removed it, which was a bit confusing.
  • Changed the behavior of the Multiple Plots dialog for printing multiple graphs on the same page. The order of the plots is now the order in which they are selected. In previous versions the plots were arranged in the order they were opened or created; selection order was ignored.
  • Added the ability to specify the line width and/or symbol size for the mean/median in Box and Whisker plots, and fixed the previously-ignored mean line width entry for Dot graphs. In addition all lines are now drawn with squared off endcaps for a cleaner appearance.
  • Added a mask option to the FillBetween macro/DDE command. This is equivalent to the Copy/Mask radio buttons on the Fill Between Curves dialog.
  • The document window caption added with a Caption command is now used as the default filename for a plot, with the addition of a ".grf" extension. If a user then saves the file, this will be used as the default filename. (In previous versions the filename would be blank.)
  • Added a line and/or symbol drawing to the Legend/Labels dialog that is updated when the curve index is changed. This should help immediately recognize a curve when the "Curve no." entry is changed.
  • Added EditRemoveSpikes macro/DDE command, which performs the same operation as the Remove Random Spikes command on the Edit menu for 2D data.
  • Bug fix: If you used Save Preferences on a plot that included version's change allowing a color key on vector plots, then subsequently used Get Preferences to read those settings with that same or a similar plot that also used that color key feature, you'd end up with an additional new color key.
  • Bug fix: On 2D contour plots for which the legend was not drawn, images copied to the clipboard might have had the right-most X axis label cropped.

9 September 2012

  • Added several new options for vector plots. You can use up to 8 colors (previous limit was 2), draw a color key, and specify the magnitudes associated with each color. Added an option to the VectorPlot command to include a heading for the optional color key, added several new options to the VectorPlotOptions command, and added a new VectorPlotColors command.
  • XY and XYXY macro/DDE commands will now accept coordinates in the text placeholder form $X(i,j), $Y(i,j). Previous versions would accept only numbers.
  • Added options to the Directory macro/DDE command that allow you to set the default directory to the last folder used by manual File Open, Append, or Save As commands.
  • Modified the behavior of the Histogram and SwitchX macro/DDE commands so that the active document for any subsequent macro commands becomes the newly-created document. In the case of SwitchX this only applies to creating a new document. For macros this change is straightforward:

    XAxisLabel("This is a new document")

    will result in "This is a new document" being used as the X axis label for the newly-created document. For DDE (i.e. dplotlib.dll calls to DPlot_Command) it requires a few extra steps. In C:
    char szNumber[32];
    DWORD dwSize;

    dwSize = sizeof(szNumber);
    DocNum = atoi(szNumber);
    DPlot_Command(DocNum,"[XAxisLabel(\"This is a new document\")]");

  • Bug fix: Including the "Coefficient of variation" in the Group Summary of 1D plots caused DPlot to crash if the mean of any group was 0. (Essentially an untrapped divide by 0 error.)

29 July 2012

  • Added Replace Data command on the Edit menu and corresponding EditReplaceData macro/DDE command. This command allows you to replace the data in a destination curve with the data from a source curve, then delete the source curve. This command is especially useful if you have a saved plot for which one or more curves should be updated. That source curve might be added with File>Append, Paste, by generating a curve with Y=f(X), etc.
  • DPlot will now read up to 4 title lines from CSV and text files at the start of the file. Previous versions were limited to 3 lines.
  • DPLOTLIB programming examples are now an optional component of the setup program. In versions and they were automatically installed.
  • Bug fix: The FileSaveAs macro command failed when attempting to save a file to a UNC path.

9 July 2012

  • Bug fix: Version attempted to fix a problem with the legend in XY plots being clipped when printed, and it worked well if there was a legend. If there wasn't, the plot was generally printed too small, making room for a non-existant legend.

1 July 2012

  • Added support for Delphi for calls to DPLOTLIB.DLL. All code has been provided by Serge Astaf'ev. Thank you, Serge! DPLOTLIB example programs and source (all supported languages) are now included with the distributions for the full version of DPlot and may be found in the \DPLOTLIB folder below dplot.exe.
  • Added Xmin, Xmax, Ymin, and Ymax to the status bar display for 3D/4D plots. These values are for the visible portion of the plot, which might have been changed by zooming or by using the Extents/Intervals/Size command.
  • Added $VZMIN, $VZMAX, $VZAVG, $VXMIN, $VXMAX, $VYMIN, and $VYMAX text shortcuts. The latter four correspond to the values mentioned above. The first 3 correspond to the Z values shown in the status bar in previous versions.
  • The X values consisting of times are always sequential General Options setting was previously ignored for data sent to DPlot via DDE (Excel Add-In, for example). So if your input times passed through midnight one or more times, the plot was a jumbled mess with a maximum extent of 1 day.
  • Bug fix: The sequential time setting mentioned above was respected for Copy/Paste operations but was handled incorrectly, with 24 (hours) added to input values rather than 1 (1 day). This bug came up when adding the Time of day (fractional days) number format.
  • Bug fix: If you moved the legend of an XY plot outside the extents of the plot, the legend might get clipped when printed, though there was plenty of room on the page if the entire plot was shifted in the opposite direction.
  • Bug fix: The "Y=A+B*ln(X)+C*(ln(X))^2+..." equation form of the "More Curve Fits" plugin failed for non-positive Y values.
  • Bug fix: The Differentiate command flubbed the first X value for the quadratic method unless Replace existing curves was checked.

8 June 2012

  • Better results for saved bitmap images on Windows Vista and later Windows versions.
    DPlot now uses a workaround for a Windows problem when saving bitmap images with a positive resolution value. On most desktop systems Windows correctly reports the physical size of the screen, which is used to scale line widths, symbol sizes, position for labels, etc. On (at least) Windows 7, Windows reports a very wrong value for that width (for example a 16 inch wide display is reported as over 26 inches wide). This error resulted in distorted bitmaps saved on these systems if you used a resolution setting over 100 dpi. On Windows Vista and later versions, DPlot now ignores that value and estimates the physical screen width based on a 100 dpi screen, which coupled with the following change makes bitmap images saved in DPlot consistent regardless of comptuer system.
  • Saved bitmap image sizes should now be consistent on all systems.
    When saving bitmap images with a resolution setting greater than 100 dpi, DPlot now scales the bitmap dimensions up by <resolution>/(100 dpi). Previously DPlot used <resolution>/<screen resolution>. Although consistent with the gimmick used to create high resolution images, this resulted in inconsistent bitmap sizes saved on different systems with the identical save settings.
  • X,Y|,Z| Labels are now saved to and restored from preference files.
  • The Find Volume Under Surface command now also calculates the average Z for points above and below the specified base Z.
  • All plugins distributed with DPlot now take double-precision arrays (8-byte floating point) rather than single-precision (4-byte). Single-precision plugins from other sources are still supported, though not recommended for plugin authors for reasons that follow.
    When first released and for several years after, DPlot stored all data as single-precision floating point numbers (4 bytes) rather than double-precision (8-bytes), and the plugin modules distributed with DPlot also worked with single-precision values. This was done solely to reduce the memory requirements of DPlot. Since switching to double-precision, DPlot will work with either single- or double-precision plugins, and for the most part this works well. An exception to this was recently pointed out by a user for the Baseline Shift plugin: the user had time values in the neighborhood of 1311 seconds with a time step of 24 microseconds. Simply converting these times to single-precision and back to double-precision caused a rather severe precision problem with decimal places wiped out, even though the plugin did not operate on the time values at all. All plugins now distributed with DPlot are double-precision. This effects the Baseline Shift plugin and also the Hi-Techniques Win600 file import plugin.

17 May 2012

  • Bug fix: Rearranging a few things in to handle polar plot legends ended up breaking the legend resulting from using Y=f(X,Y1,Y2,...).

13 May 2012

  • Added DeleteImage macro command, which removes images added with a previous InsertImage command or the Insert Image command on the Options menu.
  • Amended calculation of $MEAN, $STDEV, and similar placeholders to take account of Amplitude Limits settings. Points outside those limits are now ignored.
  • Amended legend generation for Y=f(X) and similar commands for polar coordinates. For polar plots, X or x are replaced by θ and Y or y are replaced by r. Note that this substitution only takes place if Polar Coordinates has been specified before generating the new curve.
  • Expanded the capabilities of the Differentiate a Curve command. You may now perform this operation on multiple curves and optionally replace the source curves with the result. If the source curve has a legend then the output curve's legend is set to "∂/∂x( <legend> )". Similarly, the legend for a curve created with the Integrate a Curve command will now be set to "∫<legend>".
  • Amended behavior of ColumnsAre macro command. [ColumnsAre(0)] did esentially nothing in previous versions: the "Specify Columns to Plot" dialog was still shown if that was the default setting. You could only bypass that dialog by specifying all of the column numbers. In this version [ColumnsAre(0)] results in the same behavior as not checking "Pick Columns to Plot" box: X values are read from the first column and subsequent columns are used for Y values all sharing the same X.
  • When saving tab- or comma-separated text files, DPlot always wrote dates using "M/d/yyyy" format. This made alignment in text editors problematic, but worse, made the files unworkable for reading into DPlot if you had set Assume input dates are of the form d/m/y under the General Options menu command. This version uses either "MM/dd/yyyy" or "dd/MM/yyyy" date formatting.
  • Added a "Backward" option to the "Make Step Plot" plugin module on the Generate menu.
  • Bug fix: DPlot has for many versions interpreted "NAN", "nan", "NaN" as "not a number" (a divide by zero or other math error) in text files. So it was interpreted as a number, though an illegal one that was skipped over. This worked fine unless you had a column of labels with one or more entries containing that sequence, e.g. Nancy or Financial. In that case DPlot would usually decide that the next line was where the data started, since the data types didn't match (label vs. number). This version is a bit smarter about detecting NaN's. NaN's are detected for "NAN", "nan", or "NaN" in a 3 (and only 3) character column, and for "#QNAN;" in any position, which is common in Campbell Scientific Datalogger files.
  • Bug fix: If "Time of day (fractional days)" number format was used on date and time values then only the time (not the date) was displayed in the Extents/Intervals/Size dialog. When you clicked OK DPlot attempted to read a date and time from the text boxes and set the date to 0 (December 31, 1899). In this release DPlot still displays times only, but preserves the initial date and adds it back to text box values on exit.

31 March 2012

  • Added a "Hide" option for individual reference lines.
  • For licensed users only, added a file import plugin for Pacific Instruments BEU files.
  • "List Peaks in Range" now works with 2D views of 3D and 4D surface plots, in addition to XY plots.
  • Modified the Polynomial Curve Fit and Histogram menu commands to ignore points with Y values outside the limits set with Amplitude Limits.
  • Applied the same Amplitude Limits change to all Generate menu plugins that produce new data in the same plot (as opposed to replacing existing data or creating a new document). (For plugin authors, you must use version 4 of the plugin interface to take advantage of this change. Contact us if you have any questions about this.)

    For Generate menu plugins that produce a new document, all points are preserved but the Amplitude Limits settings, if any, are now applied to the new document. Note that depending on what the plugin does, the new data may still be influenced by Y values outside the limits. If that is a problem, crop those values with the Crop or Clip Y commands on the Edit menu before using the plugin.

  • Added a DeleteNote macro/DDE command to delete notes previously added with the various TextNote commands or the Add/Edit Note menu command.
  • Most 3D/4D settings are now preserved when creating a new surface plot using Generate Mesh.
  • Removed inapplicable right-click menu items for bar charts (line style, symbol style and size)
  • Bug fix: DPlot did not properly save text notes with embedded \n sequences (new line) that were added with NoteText, TextNote, TextNote3D, or TextNoteEx commands to DPlot files. When re-reading such a file DPlot would lose track of the end of the note and usually complain about an unsupported keyword.
  • Bug fix: Tab alignment in text notes did not work properly in lines containing control codes (subscripts, underline, etc.)
  • Bug fix: Legend entries generated by DPlot commands (rather than those typed by the user) might not have been saved properly to comma- or tab-separated value files, perhaps leaving off a trailing quotation mark. This made then opening the files in Excel problematic.
  • Bug fix: Curve labels might have been cropped in images copied to the Clipboard or saved as image files with "Crop white space" checked.

12 February 2012

  • Improvements for multiple-column text files (e.g. CSV files):
    • DPlot now handles up to three column heading lines. If more than one column heading line is found ("found" meaning a line determined to contain text labels contains as many comma‑, tab‑, or semicolon‑delimited columns as the data), the associated legend or axis label entry will include a comma between respective heading entries.
    • In previous versions title lines not surrounded with double-quotation marks were truncated at the first comma, if a comma was present. In this release the entire line is used.
  • Added angle from horizontal output to the "Distance from..." menu command for 2D data.
  • Added a check against too many (too many in this case being an arbitrary >2000) tick marks/grid lines for XY plots. If the "Specify Interval" setting would result in more than 2000 grid lines, DPlot turns off that setting and automatically picks an interval on both axes.
  • Bug fix: 3D/4D plots with "Label every __" (contour level) might have crashed after performing an operation (e.g. Operate on Z) that resulted in the contour levels being reset to a value smaller than the "Label every __" value.
  • Bug fix: The Playback command did not show line segments in the legend of a plot.
  • Bug fix: Copied bitmaps and metafiles were forced to be wide enough to accommodate the unformatted title lines and axis labels. In other words, the calculated width included all formatting codes. This might have resulted in bitmaps or metafiles having too much white space at the left and right sides of the plot.
DPlot Revision Archives
"DataTaker now supplies a copy of the popular DPlot software program with every new DT80, DT82E, DT85, DT80G and DT85G. DPlot and DataTaker have produced a custom plug-in that allows DataTaker binary files to open directly with DPlot for analysing. DPlot is available as a 30 day trial download for existing DataTaker users and a full licence can be purchased online from the DPlot website."
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