Add watermarks to gif animations with improved performance

Yesterday's implementation was very inefficient. It took about 10 seconds. Today, I improved the GIF encoder again, but the efficiency was not improved. Basically, I added watermarks to gif images, however, a transparent GIF still has problems when adding watermarks, so we have time to study it again.
Original GIF

The image after the watermark is:

However, there are some problems with the transparent background.
Source image

After watermark

Modified part

1 Protected   Void Getimagepixels ()
2 {
3 Int W = Image. width;
4 Int H = Image. height;
5 // Int type = image. GetType ().;
6 If (W ! = Width)
7 | (H ! = Height)
8 )
9 {
10 // Create new image with right size/format
11 Image temp =
12 New Bitmap (width, height );
13 Graphics g = Graphics. fromimage (temp );
14 G. drawimage (image, 0 , 0 );
15 Image = Temp;
16 G. Dispose ();
17 }
18 /**/ /*
19Todo:
20Improve Performance: use unsafe code
21*/
22 Pixels =   New Byte [ 3   * Image. Width * Image. Height];
23 Int Count =   0 ;
24 Bitmap tempbitmap =   New Bitmap (image );
25 Int Wh = Image. width;
26 Int He = Image. height;
27 System. Drawing. imaging. bitmapdata BMP data = Tempbitmap. lockbits ( New Rectangle ( 0 , 0 , Wh, He), system. Drawing. imaging. imagelockmode. readwrite, image. pixelformat );
28 Unsafe
29 {
30 Byte * P = ( Byte * ) BMP data. scan0.topointer ();
31 For ( Int I =   0 ; I <   4   * Wh * He; I + =   4 )
32 {
33 Pixels [count] =   * (P + I + 2 );
34 Count ++ ;
35 Pixels [count] =   * (P + I +   1 );
36 Count ++ ;
37 Pixels [count] =   * (P + I );
38 Count ++ ;
39 }
40 }
41 Tempbitmap. unlockbits (BMP data );
42 // Count = 0;
43 // For (INT th = 0; th <image. height; th ++)
44 // {
45 // For (INT Tw = 0; TW <image. width; TW ++)
46 // {
47 // Color color = tempbitmap. getpixel (TW, th );
48 // Pixels [count] = color. R;
49 // Count ++;
50 // Pixels [count] = color. g;
51 // Count ++;
52 // Pixels [count] = color. B;
53 // Count ++;
54 // }
55 // }
56
57 // Pixels = (databufferbyte) image. getraster (). getdatabuffer (). getdata ();
58 }

Comments are originalCode
There are still two problems:
1) Transparent background
2) The size of the generated file increases.
Hope for more advice