title: $:/plugins/tiddlywiki/dynaview/docs

! Documentation

The components of this plugin include:

* A background task that:
** performs specified actions when elements are scrolled into view
** updates certain base classes on the `document.body` according to the current zoom level
** if enabled in the DynaView config panel - dynamically stores the viewport dimensions in $:/state/viewport/width and $:/state/viewport/height
* Pre-configured CSS classes to simplify using those base classes
* Usage examples

! Scroll Features

The background task detects when elements with the class `tc-dynaview-set-tiddler-when-visible` scroll into view. The first time that they do, the background task assigns the value in the attribute `data-dynaview-set-value` to the tiddler whose title is in the attribute `data-dynaview-set-tiddler`. This assignment can be tied to a reveal widget to cause content to be displayed when it becomes visible. If the class `tc-dynaview-expand-viewport` is set then the viewport is expanded so that the processing occurs when elements move near the viewport.

! Viewport Size Features

!! Viewport Size Tracking

The background task can optionally dynamically update a pair of state tiddlers with the dimensions of the browser viewport.

* Set the configuration tiddler $:/config/DynaView/ViewportDimensions to the text "yes" to enable this feature
* The viewport dimensions can be found in $:/state/DynaView/ViewportDimensions/Width and $:/state/DynaView/ViewportDimensions/Height

!! Font "Optisizer"

The background task can optionally dynamically optimise the font size of a passage of text to match a desired line length.

* Set the configuration tiddler $:/config/DynaView/Optisizer to the text "yes" to enable this feature
* Optionally, update the configuration tiddler $:/config/DynaView/Optisizer/Text with the "maquette" -- a character string matchng the desired length (this string should not include spaces).
* Assign the following CSS classes to appropriate elements on the page:
** `.tc-dynaview-optisizer-site` for an HTML element whose `offsetWidth` property gives the desired output width
** `.tc-dynaview-optisizer-maquette` for an HTML element that will contain the maquette
* The computed optimum font size can be found in the tiddler $:/state/DynaView/Optisizer/FontSize

The tiddler $:/plugins/tiddlywiki/dynaview/optisizer-maquette contains an example configuration that can be used to adjust the size of tiddler body text. To use it:

* Set $:/config/DynaView/Optisizer to the text "yes"
* Set $:/themes/tiddlywiki/vanilla/metrics/bodyfontsize to `{{$:/state/DynaView/Optisizer/FontSize}}`
* Set $:/themes/tiddlywiki/vanilla/metrics/bodylineheight to `1.5` to ensure that the line height matches the font size

! Zoom Features

!! Document Body Zoom Classes

The background task sets the following classes on `document.body` according to the current zoom level.

|!Class |!Description |
|`tc-dynaview-zoom-factor-1` |Set when the zoom level is less than 2.00 |
|`tc-dynaview-zoom-factor-2` |Set when the zoom level is greater than 2.00 and less than 3.00 |
|`tc-dynaview-zoom-factor-3` |Set when the zoom level is greater than 3.00 and less than 4.00 |
|`tc-dynaview-zoom-factor-4` |Set when the zoom level is greater than 4.00 |
|`tc-dynaview-zoom-factor-1-and-above` |Set when the zoom level is greater than or equal to 1.00 |
|`tc-dynaview-zoom-factor-1a-and-above` |Set when the zoom level is greater than or equal to 1.14 |
|`tc-dynaview-zoom-factor-1b-and-above` |Set when the zoom level is greater than or equal to 1.33 |
|`tc-dynaview-zoom-factor-1c-and-above` |Set when the zoom level is greater than or equal to 1.60 |
|`tc-dynaview-zoom-factor-2-and-above` |Set when the zoom level is greater than or equal to 2.00 |
|`tc-dynaview-zoom-factor-2a-and-above` |Set when the zoom level is greater than or equal to 2.66 |
|`tc-dynaview-zoom-factor-3-and-above` |Set when the zoom level is greater than or equal to 3.00 |
|`tc-dynaview-zoom-factor-4-and-above` |Set when the zoom level is greater than or equal to 4.00 |

!! Pre-configured Classes

These classes can be used on any element to control its visibility at different zoom levels.

|!Class |!Description |
|`tc-dynaview-zoom-visible-1-and-above` |Visible when the zoom level is 1.00 or more |
|`tc-dynaview-zoom-visible-1a-and-above` |Visible when the zoom level is 1.14 or more |
|`tc-dynaview-zoom-visible-1b-and-above` |Visible when the zoom level is 1.33 or more |
|`tc-dynaview-zoom-visible-1c-and-above` |Visible when the zoom level is 1.60 or more |
|`tc-dynaview-zoom-visible-2-and-above` |Visible when the zoom level is 2.00 or more |
|`tc-dynaview-zoom-visible-2a-and-above` |Visible when the zoom level is 2.66 or more |
|`tc-dynaview-zoom-visible-3-and-above` |Visible when the zoom level is 3.00 or more |
|`tc-dynaview-zoom-visible-4-and-above` |Visible when the zoom level is 4.00 or more |
|`tc-dynaview-zoom-visible-1` |Visible when the zoom level is less than 2.00 |
|`tc-dynaview-zoom-visible-2` |Visible when the zoom level is greater than or equal to 2.00 and less than 3.00 |
|`tc-dynaview-zoom-visible-3` |Visible when the zoom level is greater than or equal to 3.00 and less than 4.00 |
|`tc-dynaview-zoom-visible-4` |Visible when the zoom level is greater than or equal to 4.00 |