PDFTron WebViewer

Class: SelectionModel

Core.Annotations. SelectionModel

Represents a class that contains information about how an annotation should behave when selected.

new SelectionModel(annotation, canModify, isSelected, docViewer)

Create a new selection model.
Parameters:
Name Type Description
annotation Core.Annotations.Annotation The annotation selected
canModify boolean Modification of the annotation is allowed
isSelected boolean The annotation is already selected
docViewer Core.DocumentViewer An instance of DocumentViewer.

Members

<static> defaultNoPermissionSelectionOutlineColor

Defines the default color for the annotation selection outline when the user is not permitted to make modifications.
Type:

<static> defaultSelectionOutlineColor

Defines the default color for the annotation selection outline.
Type:

<static> selectionAccuracyPadding

Defines padding for selection accuracy. Default is 2. Increase this value to make selection more forgiving.
Type:
  • number

<static> selectionOutlineDashSize

Defines the dash size for the selection outline. Default is 4;
Type:
  • number

<static> selectionOutlineExtraPadding

Defines the default padding between selection control points. The padding only appears when the control points are too close.
Type:
  • number

<static> selectionOutlineThickness

Defines thickness of the annotation selection outline. Default is 1.
Type:
  • number

<static> showPaddingWhenAnnotationIsSmall

Defines if extra padding should be shown when the selected annotation is too small. Default is true.
Type:
  • boolean

<static> useDashedLine

Defines if a dashed line style should be used for the selection outline. Default is false.
Type:
  • boolean

Methods

<static> setCustomHandlers(selectionModelClass, selectionModelCustomHandlers)

Overwrites the functions in SelectionModel(ex: drawSelectionOutline, getDimensions, testSelection).
Parameters:
Name Type Description
selectionModelClass Core.Annotations.SelectionModel The class (constructor) of the selectionModel
selectionModelCustomHandlers Core.Annotations.SelectionModel.SelectionModelCustomHandlers An object containing multiple handlers to overwrite functions on a SelectionModel.
Example
const { Annotations } = instance.Core;
const { SelectionModel, BoxSelectionModel } = Annotations;
SelectionModel.setCustomHandlers(BoxSelectionModel, {
  // draws a diagonal dashed along across the middle of the selected annotation
   drawSelectionOutline(ctx, annotation, zoom, pageMatrix, { selectionModel, originalDrawSelectionOutline }) {
     if (!(annotation instanceof Annotations.RectangleAnnotation)) {
         originalDrawSelectionOutline(ctx, annotation, zoom, pageMatrix);
         return;
       }
      if (typeof zoom !== 'undefined') {
         ctx.lineWidth = SelectionModel.selectionOutlineThickness / zoom;
       } else {
         ctx.lineWidth = SelectionModel.selectionOutlineThickness;
       }
       if (selectionModel.canModify()) {
         ctx.strokeStyle = SelectionModel.defaultSelectionOutlineColor.toString();
       } else {
         ctx.strokeStyle = SelectionModel.defaultNoPermissionSelectionOutlineColor.toString();
       }
       ctx.beginPath();
       ctx.moveTo(annotation.X, annotation.Y);
       ctx.lineTo(annotation.X + annotation.Width, annotation.Y + annotation.Height);
       ctx.closePath();
       ctx.stroke();
       const dashUnit = SelectionModel.selectionOutlineDashSize / zoom;
       const sequence = [dashUnit, dashUnit];
       ctx.setLineDash(sequence);
       ctx.strokeStyle = 'rgb(255, 255, 255)';
       ctx.stroke();
     },
    // Get the dimension that is extended by 8 both horizontally and vertically
    getDimensions(annotation, { selectionModel, originalGetDimensions }) {
     if (!(annotation instanceof Annotations.RectangleAnnotation)) {
        return originalGetDimensions(annotation);
     }
     const x = annotation.X - 4;
     const y = annotation.Y - 4;
     const width = annotation.Width + 2 * 4;
     const height = annotation.Height + 2 * 4;
     return new Annotations.Rect(x, y, x + width, y + height);
    },
    testSelection(annotation, x, y, pageMatrix, zoom, rotation, { selectionModel, originalTestSelection }) {
      if (annotation instanceof Annotations.RectangleAnnotation) {
        return originalTestSelection(annotation, x, y, pageMatrix, zoom, rotation);;
      }
      return Annotations.SelectionAlgorithm.boundingRectTest(annotation, x, y, zoom);
    }
})

<static> setSelectionModelPaddingHandler(fn)

Defines a function to set selection padding on specific types of annotations.
Parameters:
Name Type Description
fn function A function that returns the padding value for specific types of annotations
Example
const { Annotations } = instance.Core;
Annotations.SelectionModel.setSelectionModelPaddingHandler((annotation) => {
 if (annotation instanceof Annotations.FreeTextAnnotation) {
   return 30;
 }
 if (annotation instanceof Annotations.RectangleAnnotation) {
   return 20;
 }
 return 0;
});

canModify()

Indicates that the associated annotation is able to be modified
Returns:
Type
boolean

drawSelectionOutline(ctx, annotation, zoom)

Draws the selection outline of the annotation. By default, a rectangle is drawn based on the annotations x, y, width and height.
Parameters:
Name Type Description
ctx CanvasRenderingContext2D
annotation Core.Annotations.Annotation
zoom number

getControlHandles()

Returns the ControlHandle objects associated with this selection model.
Returns:
An array of ControlHandleObject
Type
Array.<Core.Annotations.ControlHandle>

getDimensions(annotation)

Gets the dimensions {x, y, width, height} of the selection bounding box. It may be different from the annotation's bounding box. e.g. The selection bounding box may have a padding.
Parameters:
Name Type Description
annotation Core.Annotations.Annotation
Returns:
Type
Core.Math.Rect

isSelected()

Indicates that the associated annotation is already selected. This can be useful to implement different selection behaviors when an annotation is selected.
Returns:
Type
boolean

testControlHandles(annotation, zoom, x, y)

Hit detection for each control handle.
Parameters:
Name Type Description
annotation Core.Annotations.Annotation
zoom number
x number
y number
Returns:
The control handle that was hit
Type
Core.Annotations.ControlHandle

testSelection(annotation, x, y, pageMatrix, zoom, rotation)

Determines if the provided point is a hit on the selected annotationhandle. * See Core.Annotations.SelectionAlgorithm for usuable selection algorithms.
Parameters:
Name Type Description
annotation Core.Annotations.Annotation the annotation
x number the x-coordinate of the point to test, in page coordinates
y number the y-coordinate of the point to test, in page coordinates
pageMatrix object the page matrix of the page the annotation is on
zoom number the zoom level of the page the annotation is on
rotation Core.PageRotation the rotation of the page the annotation is on
Returns:
true if the provided point is a hit
Type
boolean

Type Definitions

CustomDrawSelectionOutlineHandler(ctx, annotation, zoom, pageMatrix, options)

Callback that gets passed to drawSelectionOutlineHandler in setCustomHandlers.
Parameters:
Name Type Description
ctx CanvasRenderingContext2D A canvas context
annotation Core.Annotations.Annotation The annotation being selected
zoom number the current zoom level of the document
pageMatrix object The transformation matrix for the page that the annotation is on
options object Additional options and parameters
Properties
Name Type Description
selectionModel Core.Annotations.SelectionModel The selection model of the annotation which is currently selected.
originalDrawSelectionOutline function The original draw function of this selection model

CustomGetDimensionsHandler(annotation, selectionBox, zoom, options)

Callback that gets passed to getDimensionsHandler in setCustomHandlers.
Parameters:
Name Type Description
annotation Core.Annotations.Annotation The annotation being selected
selectionBox Core.Math.Rect
zoom number the current zoom level of the document
options object Optional options
Properties
Name Type Description
selectionModel Core.Annotations.SelectionModel The selection model of the annotation which is currently selected.
originalGetDimensions function The original getDimensions function of this selection model
Returns:
Type
Core.Math.Rect

CustomTestSelectionHandler(x, y, pageMatrix, zoom, rotation, options)

Callback that gets passed to testSelectionHandler in setCustomHandlers.
Parameters:
Name Type Description
x number The x-coordinate of the point to test, in page coordinates
y number The y-coordinate of the point to test, in page coordinates
pageMatrix object the page matrix of the page the annotation is on
zoom number The zoom level of the page the annotation is on
rotation Core.PageRotation The rotation of the page the annotation is on
options object Optional options
Properties
Name Type Description
selectionModel Core.Annotations.SelectionModel The selection model of the annotation which is currently selected.
originalTestSelection function The original draw function of this selection model
Returns:
Type
boolean

SelectionModelCustomHandlers

A collection of functions that overwrite the original functions in SelectionModel
Type:
  • object
Properties:
Name Type Argument Description
drawSelectionOutline Core.Annotations.SelectionModel.CustomDrawSelectionOutlineHandler <optional>
 Changes how a selection model is drawn within WebViewer.
getDimensions Core.Annotations.SelectionModel.CustomGetDimensionsHandler <optional>
 Gets the rect of the selection bounding box.
testSelection Core.Annotations.SelectionModel.CustomTestSelectionHandler <optional>
 Determines if the provided point is a hit on the selected annotation handle.