WklChart

WklChart draws a chart from a table, query, or SQL statement on an Access form: a series of measurements over time with its lower and upper limits, monthly counts as columns, or values per category as bars. Like a subform, it follows the form's current record through LinkMasterFields and LinkChildFields. Because it uses its own renderer, the chart looks the same in Form view, Design view, and Print Preview.

Since release 1.60.0; in reports and with PrintStyle since 1.62.0.

• Show a measurement series with its limit and trend

• Plot the wall thickness of the current measuring point over time: RecordSource = the readings, XField = the date, YFields = the thickness, LinkMasterFields = the key on the form, LinkChildFields = the key in the readings.
• Draw the minimum and maximum: AddReference MinWall, , "Minimum", wskBad in Form_Current.
• Find out when the minimum will be reached if the trend continues: TrendReaches(0, MinWall).
• Count inspections due per month: ChartType = wctColumn, Aggregate = wcaCount, Period = wcyMonth.
• Bands, one series per measuring point from long data, and reading the trend: How to: Show limits and a trend in a chart.
• One chart per report record, legible on a grayscale printout: How to: Print gauges and charts in a report.

+- WklChart ------------------------------------------------------+
|                       TML-1 Wall thickness                      | 1
| 11.0 |                                                          |
| 10.5 |- - - - - - - - - - - - - - - - - - - - - - - - -  Maximum| 2
| 10.0 |  *-*                                                     |
|  9.5 |      *-*-*  .                                            | 3
|  9.0 |             *-*-*-*  . .                                 | 4
|  8.5 |- - - - - - - - - - - - - - - - - - - - - - - - -  Minimum|
|      +----------+----------+----------+----------+              |
|        2026       2027       2028       2029                    | 5
+-----------------------------------------------------------------+

• Data binding to a table, query, or SQL statement, with one series per Y field („wide“ data) or one series per value of a series field („long“ data).
• Follows the form like a subform through LinkMasterFields and LinkChildFields; when the master record changes, the chart reads its data again.
• Four chart types: line, point, column, and bar; columns and bars can be clustered or stacked.
• Aggregation per X value or per day, week, month, quarter, or year: sum, average, count, minimum, and maximum.
• Limits and bands with captions, in the same status colors as the other components.
• Linear trend per series, with its slope and the date it reaches a limit.
• Long series are downsampled for display, and the chart says so; the trend and the axis still use every value.
• Readable for everyone: series colors that stay distinguishable for people with color vision deficiency and keep a 3:1 contrast ratio, a distinct marker shape per series, and the same color schemes as the other components.

The X values determine the axis. XKind = wcxDate gives a time axis with calendar intervals; wcxNumber, a numeric axis with round steps (1, 2, 2.5, or 5 times a power of ten); and wcxCategory, one position per distinct text, in the order the texts first appear.

Missing values aren't made up. With Missing = wcvGap (the default), a row without a Y value breaks the line. wcvConnect skips the point, and wcvZero treats it as 0. A row without a readable X value can't be placed; instead of failing the chart, it's counted in RowsWithoutX.

Errors are displayed, not raised. The chart reads its data on its own (when the form opens and when the master record changes), outside any VBA call that could catch an error. A read error is drawn in the chart, stored in LastError, and reported through DataLoaded.

The value axis includes the limits. The Y axis always spans every limit line and band, so a limit outside the measured range is never cut off. Columns and bars start at 0.

A downsampled chart says so. A line with more points than the chart can display (more than 2,000) is downsampled with the Largest-Triangle-Three-Buckets algorithm (Steinarsson, 2013), which keeps the first and last points and the peaks; the chart then shows „reduced for display“ in its corner.

• How to: Install the released package

None yet.

• WklChart

• WklGauge: one value against its ranges, where a chart shows a series.