ShowLoClippingTiff.cs
//
// This code is part of GrapeCity Documents for Imaging samples.
// Copyright (c) GrapeCity, Inc. All rights reserved.
//
using System;
using System.IO;
using System.Drawing;
using System.Collections.Generic;
using System.Linq;
using System.Numerics;
using GrapeCity.Documents.Drawing;
using GrapeCity.Documents.Text;
using GrapeCity.Documents.Imaging;

namespace GcImagingWeb.Samples
{
    // This sample demonstrates how to find and show pixels with clipped shadows.
    // This sample is identical to ShowLoClippingJpeg but uses a TIFF image
    // rather than a JPEG created from the same source photo.
    public class ShowLoClippingTiff
    {
        public GcBitmap GenerateImage(int pixelWidth = 1024, int pixelHeight = 1024, bool opaque = true, float dpiX = 96, float dpiY = 96)
        {
            var bmp = new GcBitmap(pixelWidth, pixelHeight, opaque, dpiX, dpiY);
            using (var bmpSrc = new GcBitmap(Path.Combine("Resources", "ImagesBis", "clivia.tiff")))
            {
                // BitBlt requires the opacity of both images to be the same:
                bmpSrc.Opaque = opaque;
                // Render source image onto the target bitmap
                // (generally we might want to resize the source image first,
                // but in this case we just know that the source image has
                // the same size as the target, so skip this step):
                bmp.BitBlt(bmpSrc, 0, 0);

                using (var g = bmp.CreateGraphics())
                {
                    for (int i = 0; i < bmp.PixelWidth; ++i)
                        for (int j = 0; j < bmp.PixelHeight; ++j)
                        {
                            // If all of the colors are 0x00, we change the pixel's color to magenta:
                            if ((bmp[i, j] & 0x00FFFFFF) == 0)
                                bmp[i, j] = 0xFFFF00FF;
                        }
                    // Draw the original image in the bottom right corner for reference:
                    var rc = new RectangleF(0, 0, pixelWidth / 4, pixelHeight / 4);
                    g.DrawImage(bmpSrc, rc, null, ImageAlign.StretchImage);
                    g.DrawRectangle(rc, Color.LightGray);
                }
            }
            return bmp;
        }
    }
}