Nutrient Web SDK

ReferenceRenderPageCallback

Type Alias RenderPageCallback

This callback is called whenever a page is rendered or printed (only for NutrientViewer.PrintMode.DOM). You can use it to render watermarks on the page.

Make sure that the rendering commands are as efficient as possible as they might be invoked multiple times per page (once per tile).

For more information, see Configuration#renderPageCallback.

Type Alias
Type Signature
type RenderPageCallback = (
    context: CanvasRenderingContext2D,
    pageIndex: number,
    pageSize: NutrientViewer.Geometry.Size,
) => unknown

Example

Register a RenderPageCallback handler at configuration time.

NutrientViewer.load({
  renderPageCallback: function(ctx, pageIndex, pageSize) {
    ctx.beginPath();
    ctx.moveTo(0, 0);
    ctx.lineTo(pageSize.width, pageSize.height);
    ctx.stroke();

    ctx.font = "30px Comic Sans MS";
    ctx.fillStyle = "red";
    ctx.textAlign = "center";
    ctx.fillText(
      `This is page ${pageIndex + 1}`,
      pageSize.width / 2,
      pageSize.height / 2
    );
  }
  // ...
});

Type Declaration

Parameters

contextCanvasRenderingContext2D

A 2D <canvas/> rendering context.

pageIndexnumber

The current page index, starting with 0 for the first page.

pageSizeNutrientViewer.Geometry.Size

The size of the page that you're drawing at. The canvas is already scaled accordingly.

Returns

unknown