Highlight a region in a PDF or an image in C#

This example shows how to draw highlighted regions on top of a document. A highlighted region is a special feature that’s modifiable by mouse. It can be used to specify areas and highlight them, and it’s especially useful in anchor and OMR applications.


C#
//We assume that GdPicture has been correctly installed and unlocked.
//We assume the GdViewer object called GdViewer1 has been created and painted on the form.
GdPictureImaging oGdPictureImaging = new GdPictureImaging();
//Loading the image from a file.
int imageId = oGdPictureImaging.CreateGdPictureImageFromFile("C:\\Image.tif");
//Checking if the image resource has been loaded correctly.
if (oGdPictureImaging.GetStat() != GdPictureStatus.OK)
{
MessageBox.Show("The image can't be loaded. Error: " + oGdPictureImaging.GetStat().ToString(), "Drawing regions Example", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
else
{
//Displaying the image in the GdViewer.
GdViewer1.DisplayFromGdPictureImage(imageId);
}
oGdPictureImaging.Dispose();
//On the Mouse UP event on the GdViewer, create a highlighted region based on the rectangle of selection of the GdViewer.
//If no rectangle of selection is painted on the GdViewer, this event will do nothing.
public void Mouse_UP_Draw_Region(System.Object eventSender, System.EventArgs eventArgs)
{
//Initializing variables to hold the position of the rectangle of selection on the document.
int leftArea = 0;
int topArea = 0;
int widthArea = 0;
int heightArea = 0;
//Checking if a rectangle of selection has been painted on the GdViewer.
if (GdViewer1.IsRect())
{
//Getting the location of the selection on the document.
GdViewer1.GetRectCoordinatesOnDocument(ref leftArea, ref topArea, ref widthArea, ref heightArea);
//Setting the ROI on the document:
//Adding a region in place of the rectangle of selection.
int regionId = GdViewer1.AddRegion("Region", leftArea, topArea, widthArea, heightArea, GdPicture14.ForegroundMixMode.ForegroundMixModeMASKPEN, Color.Green);
//Setting region border width.
GdViewer1.SetRegionBorderWidth(regionId, 1);
//Setting region border color.
GdViewer1.SetRegionBorderColor(regionId, Color.Blue);
//Redrawing the whole image.
GdViewer1.ClearRect();
GdViewer1.Redraw();
}
}

This code sample is an example that illustrates how to use our SDK. Please adapt it to your specific use case.