ItextSharp smooth background shade - itext

Question

I am working on pdf using iTextSharp and product owner decided to have a "stickers" alike text boxes casting a shadow on background for it. I was searching the Internet and couldn't find a hint to how to achieve this effect. The design provided for it is as follows:
Could anybody more experienced with iText or iTextsharp help me by advising on how to achieve such effect please?
Kind regards
Karol

Answer 1

Using the hints and links in Joris' answer, one can easily implement a helper method like this to draw the shaded rounded rectangles:
void DrawRoundedShadedRectangle(PdfWriter writer, float x, float y, float w, float h, float r, float shade, BaseColor innerColor, BaseColor shadeColor, BaseColor outerColor)
{
PdfContentByte canvas = writer.DirectContent;
canvas.SaveState();
canvas.Rectangle(x - shade, y + r, w + 2 * shade, h - 2*r);
canvas.Clip();
canvas.NewPath();
PdfShading shadingRight = PdfShading.SimpleAxial(writer, x + w, y, x + w + shade, y, shadeColor, outerColor, false, false);
canvas.PaintShading(shadingRight);
PdfShading shadingLeft = PdfShading.SimpleAxial(writer, x, y, x - shade, y, shadeColor, outerColor, false, false);
canvas.PaintShading(shadingLeft);
canvas.RestoreState();
canvas.SaveState();
canvas.Rectangle(x + r, y - shade, w - 2 * r, h + 2 * shade);
canvas.Clip();
canvas.NewPath();
PdfShading shadingTop = PdfShading.SimpleAxial(writer, x, y + h, x, y + h + shade, shadeColor, outerColor, false, false);
canvas.PaintShading(shadingTop);
PdfShading shadingBottom = PdfShading.SimpleAxial(writer, x, y, x, y - shade, shadeColor, outerColor, false, false);
canvas.PaintShading(shadingBottom);
canvas.RestoreState();
canvas.SaveState();
canvas.Rectangle(x + w - r, y + h - r, r + shade, r + shade);
canvas.Clip();
canvas.NewPath();
PdfShading shadingTopRight = PdfShading.SimpleRadial(writer, x + w - r, y + h - r, r, x + w - r, y + h - r, r + shade, shadeColor, outerColor);
canvas.PaintShading(shadingTopRight);
canvas.RestoreState();
canvas.SaveState();
canvas.Rectangle(x - shade, y + h - r, r + shade, r + shade);
canvas.Clip();
canvas.NewPath();
PdfShading shadingTopLeft = PdfShading.SimpleRadial(writer, x + r, y + h - r, r, x + r, y + h - r, r + shade, shadeColor, outerColor);
canvas.PaintShading(shadingTopLeft);
canvas.RestoreState();
canvas.SaveState();
canvas.Rectangle(x - shade, y - shade, r + shade, r + shade);
canvas.Clip();
canvas.NewPath();
PdfShading shadingBottomLeft = PdfShading.SimpleRadial(writer, x + r, y + r, r, x + r, y + r, r + shade, shadeColor, outerColor);
canvas.PaintShading(shadingBottomLeft);
canvas.RestoreState();
canvas.SaveState();
canvas.Rectangle(x + w - r, y - shade, r + shade, r + shade);
canvas.Clip();
canvas.NewPath();
PdfShading shadingBottomRight = PdfShading.SimpleRadial(writer, x + w - r, y + r, r, x + w - r, y + r, r + shade, shadeColor, outerColor);
canvas.PaintShading(shadingBottomRight);
canvas.RestoreState();
canvas.SaveState();
canvas.SetColorFill(innerColor);
canvas.SetColorStroke(innerColor);
canvas.RoundRectangle(x, y, w, h, r);
canvas.FillStroke();
canvas.RestoreState();
}
For example,
DrawRoundedShadedRectangle(writer, 100, 500, 200, 100, 10, 20, BaseColor.GREEN, BaseColor.RED, BaseColor.WHITE);
draws this:
And this code
DrawRoundedShadedRectangle(writer, writer.PageSize.GetLeft(100), 300, writer.PageSize.Width - 200, 100, 10, 10, BaseColor.ORANGE, BaseColor.YELLOW, BaseColor.WHITE);
PdfContentByte canvas = writer.DirectContent;
canvas.SaveState();
canvas.Rectangle(writer.PageSize.Left, writer.PageSize.Bottom, writer.PageSize.Right, 300);
canvas.Clip();
canvas.NewPath();
DrawRoundedShadedRectangle(writer, writer.PageSize.GetLeft(100), 100, writer.PageSize.Width - 200, 200, 10, 10, BaseColor.WHITE, BaseColor.YELLOW, BaseColor.WHITE);
canvas.RestoreState();
draws this
By tweaking the radius, the shade, and all the color parameters this should become very similar to the provided design.

Answer 2

This can be done with iText.
It's a matter of using drawing operations on the canvas to achieve the effect.
in your case
- a rounded rectangle, filled with orange
- a rounded rectangle underneath it, filled with white