How can I get the Rect from a text selections Quads ?

Technical Support Apryse SDK
1

Hi,

I’m trying to find out if a selected word (double-click) is part of an highlight annotation.

It would seem that the way to do it is to get a Rect for the click word, and then compare that to all the highlight rects in the document, and if it’s within any of the existing highlight Rect’s, then I know that specific highlight is the one the user clicked on/within.

I see “Quads” as a property of the selection, but annotations are saved with Rec’s…so I need to get Rec equivalent to the Quads.

I’m using PDFViewWPF, and C#.

This what I have currently:

_pdfToolManager.CreateTool(pdftron.PDF.Tools.ToolManager.ToolType.e_text_select, null, true);

_pdfViewer.MouseUp += CurrentTool_MouseLeftButtonUp;

.
.
.
double[] selectedWordQuads = selection.GetQuads();
Rect selectedWordRect = ??? //CODE FOR GET RECT FROM QUADS

…and then call…

private Annot GetAnnotationFromRect(Rect pageCoordinate, List allDocAnnotations)
{

for (var i = 0; i < allDocAnnotations.Count; i++)
{
Annot annot = allDocAnnotations[i];

Rect rect = new Rect();
rect.x1 = annot.GetRect().x1;
rect.y1 = annot.GetRect().y1;
rect.x2 = annot.GetRect().x2;
rect.y2 = annot.GetRect().y2;

if (pageCoordinate.x1 >= rect.x1 && pageCoordinate.x2 <= rect.x2 && pageCoordinate.y1 >= rect.y1 && pageCoordinate.y2 <= rect.y2)
{
Console.WriteLine(“getAnnotationByMouseEvent - ANNOTATION EXISTS FOR CLICKED WORD”);
return annot;
}
}

return null;
}

Thanks,

Barry

2

You can run through the array of doubles that from the quads, and for every pair, make a Rect, and add that to a new array of Rects. Sorry this isn’t done for you.

An option to improve throughput, is to create a single bounding box of the quads, and then get candidate annotations. Then run again, but against each individual quad/rect to find the match.

Note, instead of doing the math at the end with all four rect points, you can just do the following.

Rect intersection = new Rect(); if(intersection.IntersectRect(selection_rect, annot_rect)) {/*...*/}

3

Do you have a more full example of this ?

I have my captured selection, and I need a pdftron.PDF.Rect from it:

double[] quads = selection.GetQuads();
int numQuads = quads.Length / 8;

if (quads.Length >= 8)
{

for (int i = 0; i < numQuads; i++)
{
quadNumber = i * 8;

double x1 = quads[quadNumber + 0];
double y1 = quads[quadNumber + 1];

double x2 = quads[quadNumber + 2];
double y2 = quads[quadNumber + 3];

double x3 = quads[quadNumber + 4];
double y3 = quads[quadNumber + 5];

double x4 = quads[quadNumber + 6];
double y4 = quads[quadNumber + 7];

pdftron.PDF.Rect pdftronRect = new Rect();
pdftronRect…

…what happens next ?

Thanks,

Barry

4

I came up with this, this afternoon, and it seems to work fairly well. It will give me an List of annots for the selection:

private List GetAnnotsFromQuads(pdftron.PDF.PDFViewWPF.Selection selection)
{
//http://www.pdftron.com/pdfnet/samplecode/PDFViewControl.xaml.cs.html

//THIS WILL CAPTURE THE WINDOWS SELECTION’S RECTS AND CONVERT THEM TO PDFtron ANNOT OBJECTS

List annotList = new List();

int quadNumber = 0;
int pageNumber = selection.GetPageNum();
double[] quads = selection.GetQuads();
int numQuads = quads.Length / 8;

if (quads.Length >= 8) //must have at least 8 points to be valid
{
Console.WriteLine("GetRectsFromQuads - numQuads: " + numQuads.ToString());

for (int i = 0; i < numQuads; i++)
{
quadNumber = i * 8;

double x1 = quads[quadNumber + 0];
double y1 = quads[quadNumber + 1];

double x2 = quads[quadNumber + 2];
double y2 = quads[quadNumber + 3];

double x3 = quads[quadNumber + 4];
double y3 = quads[quadNumber + 5];

double x4 = quads[quadNumber + 6];
double y4 = quads[quadNumber + 7];

//https://groups.google.com/forum/#!searchin/pdfnet-sdk/rect$20from$20quads/pdfnet-sdk/fP_cynRYurE/r8XczPrGOVEJ
double rectX1 = Math.Min(Math.Min(Math.Min(quads[quadNumber + 0], quads[quadNumber + 2]), quads[quadNumber + 4]), quads[quadNumber + 6]);
double rectX2 = Math.Max(Math.Max(Math.Max(quads[quadNumber + 0], quads[quadNumber + 2]), quads[quadNumber + 4]), quads[quadNumber + 6]);
double rectY1 = Math.Min(Math.Min(Math.Min(quads[quadNumber + 1], quads[quadNumber + 3]), quads[quadNumber + 5]), quads[quadNumber + 7]);
double rectY2 = Math.Max(Math.Max(Math.Max(quads[quadNumber + 1], quads[quadNumber + 3]), quads[quadNumber + 5]), quads[quadNumber + 7]);

Rect selectionRect = new Rect(rectX1, rectY1, rectX2, rectY2);
//Console.WriteLine("GetRectsFromQuads - aRect: " + rectX1.ToString() + " | " + rectY1.ToString() + " | " + rectX2.ToString() + " | " + rectY2.ToString());

ColorPt defaultColour = new ColorPt(250, 246, 5, 0.3);;
Annot highlightAnnot = CreateHighlightAnnot(_pdfDocument, selectionRect, defaultColour);

annotList.Add(highlightAnnot);

//--------------------------------------------------------------------
//DEBUG TEST - REVERSE OF PDFtron BACK TO WINDOWS SELECTION
//(this should highlight the exact same text just selected)

List<System.Windows.Shapes.Rectangle> _onScreenSelection = new List<System.Windows.Shapes.Rectangle>();
System.Windows.Controls.Canvas annotCanvas = _pdfViewer.GetCanvas();

foreach (Annot annot in annotList)
{
Rect aRect = annot.GetRect();

pdftron.SDF.Obj quadPoints = annot.GetSDFObj().PutArray(“QuadPoints”);
quadPoints.PushBackNumber(aRect.x1);
quadPoints.PushBackNumber(aRect.y2);
quadPoints.PushBackNumber(aRect.x2);
quadPoints.PushBackNumber(aRect.y2);
quadPoints.PushBackNumber(aRect.x1);
quadPoints.PushBackNumber(aRect.y1);
quadPoints.PushBackNumber(aRect.x2);
quadPoints.PushBackNumber(aRect.y1);

quadNumber = i * 8;
x1 = quads[quadNumber + 0];
y1 = quads[quadNumber + 1];

x2 = quads[quadNumber + 2];
y2 = quads[quadNumber + 3];

x3 = quads[quadNumber + 4];
y3 = quads[quadNumber + 5];

x4 = quads[quadNumber + 6];
y4 = quads[quadNumber + 7];

_pdfViewer.ConvPagePtToScreenPt(ref x1, ref y1, pageNumber);
_pdfViewer.ConvPagePtToScreenPt(ref x2, ref y2, pageNumber);
_pdfViewer.ConvPagePtToScreenPt(ref x3, ref y3, pageNumber);
_pdfViewer.ConvPagePtToScreenPt(ref x4, ref y4, pageNumber);

double left, right, top, bottom;

left = Math.Min(x1, Math.Min(x2, Math.Min(x3, x4)));
right = Math.Max(x1, Math.Max(x2, Math.Max(x3, x4)));
top = Math.Min(y1, Math.Min(y2, Math.Min(y3, y4)));
bottom = Math.Max(y1, Math.Max(y2, Math.Max(y3, y4)));

System.Windows.Rect windowsRect = new System.Windows.Rect(left, top, right - left, bottom - top);

System.Windows.Shapes.Rectangle highlight = new System.Windows.Shapes.Rectangle();
highlight.Fill = new System.Windows.Media.SolidColorBrush() { Color = System.Windows.Media.Colors.Red };
highlight.Fill.Opacity = 0.3;
highlight.Width = windowsRect.Width;
highlight.Height = windowsRect.Height;
System.Windows.Controls.Canvas.SetLeft(highlight, windowsRect.Left + _pdfViewer.GetHScrollPos());
System.Windows.Controls.Canvas.SetTop(highlight, windowsRect.Top + _pdfViewer.GetVScrollPos());
annotCanvas.Children.Add(highlight);
_onScreenSelection.Add(highlight);
}
//--------------------------------------------------------------------

}

}

Console.WriteLine("GetRectsFromQuads - TOTAL RECTS FOR HIGHLIGHT: " + annotList.Count.ToString());

return annotList;
}

//HELPERS

// Use PDFNet to generate appearance stream for highlight annotation.
public pdftron.SDF.Obj CreateHighlightAppearance(PDFDoc doc, pdftron.PDF.Rect bbox, ColorPt higlight_color)
{

ElementBuilder build = new ElementBuilder();
ElementWriter writer = new ElementWriter();
writer.Begin(doc);

// Draw background
Element element = build.CreateRect(bbox.x1 - 2, bbox.y1, bbox.x2 + 2, bbox.y2);
element.SetPathFill(true);
element.SetPathStroke(false);
GState gs = element.GetGState();
gs.SetFillColorSpace(ColorSpace.CreateDeviceRGB());
gs.SetFillColor(higlight_color);
gs.SetBlendMode(GState.BlendMode.e_bl_multiply);
writer.WriteElement(element);
pdftron.SDF.Obj stm = writer.End();

build.Dispose();
writer.Dispose();

// Set the bounding box
stm.PutRect(“BBox”, bbox.x1, bbox.y1, bbox.x2, bbox.y2);
stm.PutName(“Subtype”, “Form”);
return stm;
}

// Create Highlight Annotation.
public Annot CreateHighlightAnnot(PDFDoc doc, pdftron.PDF.Rect rect, ColorPt highlight_color)
{
Annot a = Annot.Create(doc, Annot.Type.e_Highlight, rect);
a.SetColor(highlight_color);
a.SetAppearance(CreateHighlightAppearance(doc, rect, highlight_color));

pdftron.SDF.Obj quads = a.GetSDFObj().PutArray(“QuadPoints”);
quads.PushBackNumber(rect.x1);
quads.PushBackNumber(rect.y2);
quads.PushBackNumber(rect.x2);
quads.PushBackNumber(rect.y2);
quads.PushBackNumber(rect.x1);
quads.PushBackNumber(rect.y1);
quads.PushBackNumber(rect.x2);
quads.PushBackNumber(rect.y1);
return a;
}

…so that takes care of “You can run through the array of doubles that from the quads, and for every pair, make a Rect, and add that to a new array of Rects. Sorry this isn’t done for you.”

So, in your opinion what would be the most efficient way to look for over-lapping annotations at this point ?

A “bounding box” sounds interesting, but it can’t be a “x1, y1, x2, y2” rectangle because that will potentially include words that weren’t selected (highlighted) by the user, they just happened to exist int he same overall area…

thanks,

Barry

5

This helped…gleaned it from another posting (RectUnion is the meat of it, and what I am now using as a parent Rect to all the indovidual Rects withing from each created Annot, from the Quads):

private static Annot CreateBoundingAnnot(PDFDoc doc, List bboxes, ColorPt highlight_color) {

Annot boundingAnnot = Annot.Create(doc, Annot.Type.e_Highlight, RectUnion(bboxes));
return boundingAnnot;
}

public static Rect RectUnion(List boxes)
{
double y1 = boxes.Select(box => box.y1).Min();
double y2 = boxes.Select(box => box.y2).Max();
double x1 = boxes.Where(box => box.y1 == y1).Select(box => box.x1).Min();
double x2 = boxes.Where(box => box.y2 == y2).Select(box => box.x2).Max();
return new Rect(x1, y1, x2, y2);
}