Black and White Image Converter

[SMcNeill]

So, as you guys may have noticed in the discussion forum, I'm currently playing around and working with a little Xmas program which should have several little games in it.  The first "game" which I'm working on is a simple coloring book style program which lets you have fun and color, save, or print some Christmas pictures.  One glitch which I was hit with right off the bat is the problem with PAINT failing and coloring the whole dang screen at once.   The reason?? 

The images are grayscale and have multiple shades of black in them, which doesn't form a nice single color for either coloring or a border.   (It's always something to distract a person when trying to program, now ain't it!)

My solution:

Code: QB64: [Select]

1.  WS = _NewImage(600, 360, 32)
2.  
3. Screen WS
4. ReDim As String D(0), F(0)
5. GetLists "Coloring Sheets", D(), F()
6.  
7. For i = 1 To UBound(f)
8.     image = _LoadImage("Coloring Sheets/" + F(i), 32)
9.     _PutImage , image: _FreeImage image
10.     _Dest CS: _Source WS
11.     Sleep
12.     For x = 0 To 599
13.         For y = 0 To 359
14.             r = _Red32(Point(x, y))
15.             g = _Green32(Point(x, y))
16.             b = _Blue32(Point(x, y))
17.             If r > 200 Or g > 200 Or b > 200 Then PSet (x, y), &HFFFFFFFF Else PSet (x, y), &HFF000000
18.         Next
19.     Next
20.     Sleep
21. Next
22.  
23.  
24.  
25.  
26. Sub GetLists (SearchDirectory As String, DirList() As String, FileList() As String)
27.     Declare CustomType Library ".\direntry"
28.         Function load_dir& (s As String)
29.         Function has_next_entry& ()
30.         Sub close_dir ()
31.         Sub get_next_entry (s As String, flags As Long, file_size As Long)
32.     End Declare
33.  
34.     Dim flags As Long, file_size As Long, DirCount As Long, FileCount As Long, length As Long
35.     Dim nam$, slash$
36.     ReDim _Preserve DirList(1000), FileList(1000)
37.     DirCount = 0: FileCount = 0
38.     $If WIN Then
39.         slash$ = "\"
40.     $Else
41.         slash$ = "/"
42.     $End If
43.     If Right$(SearchDirectory$, 1) <> "/" And Right$(SearchDirectory$, 1) <> "\" Then SearchDirectory$ = SearchDirectory$ + slash$
44.  
45.     If load_dir(SearchDirectory + Chr$(0)) Then
46.         Do
47.             length = has_next_entry
48.             If length > -1 Then
49.                 nam$ = Space$(length)
50.                 get_next_entry nam$, flags, file_size
51.                 If _DirExists(SearchDirectory + nam$) Then
52.                     DirCount = DirCount + 1
53.                     If DirCount > UBound(DirList) Then ReDim _Preserve DirList(UBound(DirList) + 100)
54.                     DirList(DirCount) = nam$
55.                 ElseIf _FileExists(SearchDirectory + nam$) Then
56.                     FileCount = FileCount + 1
57.                     If FileCount > UBound(FileList) Then ReDim _Preserve FileList(UBound(FileList) + 100)
58.                     FileList(FileCount) = nam$
59.                 Else 'This else should never actually trigger
60.                     Print: Print: Print "zzz...  Unknown file found: "; SearchDirectory; slash$; nam$, _DirExists(nam$)
61.                     Beep: Sleep ' alert the user to
62.                 End If
63.             End If
64.         Loop Until length = -1
65.     End If
66.     close_dir
67.  
68.     ReDim _Preserve DirList(DirCount)
69.     ReDim _Preserve FileList(FileCount)
70. End Sub
71.  

Now, I can either SaveImage these into the world's smallest JPG/PNG (I can't imagine they'd be very large at all once compression hits with only 2 colors involved in each image), or I can just use the converter as is in my main program and transform those into two color images on the fly for my coloring app. 

With the two SLEEP statements in there, you can see the subtle difference as our almost-whites and almost-blacks end up turning into solid-whites and solid-blacks. 

I don't imagine there'll be any issues now with PAINT being able to find the proper borders for the images fill areas.  ;)

[Petr]

@SMcNeill
Hi. The reason you have gray pixels in your images is that JPG compression is used, because you know that JPG adds up adjacent pixels during compression. Black + white = gray. The only format that won't do this to you is either PNG or BMP. With that BMP, you would even reach half the file size (height x width / 8) + 62 bytes (compared to the current JPG file size), but it would probably be easiest to convert to PNG using your library, it is a lossless format and so it should not do artifacts after you run your program to get a black and white image from thij JPGs. I appreciate your idea, the coloring books are perfect.

After all - I don't believe my eyes. Do you use POINT and PSET? You, our teacher with MEM?    :) 

[johnno56]

Hmm... I get an error: LIBRARY not found on current line. Caused by (or after): "DECLARE CUSTOMTYPE LIBRARY ".\\direntry",10

[SMcNeill]

Hmm... I get an error: LIBRARY not found on current line. Caused by (or after): "DECLARE CUSTOMTYPE LIBRARY ".\\direntry",10

Aye.  You'll need the direntry.h library for it to work with the GetDir sub.  Just do a quick search of the forums; there's a thousand copies of it on here already.  It's just like falcon.h -- a header file which everyone should have and keep in their QB64 folder, in my opinion.  ;)

[johnno56]

Thanks Steve.

direntry.h and falcon.h ... will do...

I should have remembered that... but, for a newbie, a list dependencies might be helpful... or a link to them... ;)

[johnno56]

Steve,

'falcon' was already there... But, with 'direntry', the program ran without error.

Thank you for the assist. Much appreciated.

J

[SMcNeill]

@SMcNeill
Hi. The reason you have gray pixels in your images is that JPG compression is used, because you know that JPG adds up adjacent pixels during compression. Black + white = gray. The only format that won't do this to you is either PNG or BMP. With that BMP, you would even reach half the file size (height x width / 8) + 62 bytes (compared to the current JPG file size), but it would probably be easiest to convert to PNG using your library, it is a lossless format and so it should not do artifacts after you run your program to get a black and white image from thij JPGs. I appreciate your idea, the coloring books are perfect.

After all - I don't believe my eyes. Do you use POINT and PSET? You, our teacher with MEM?    :)

I almost always start out with POINT and PSET to get things working, and then swap over to MEM when speed is the concern.

Many thanks in reminding me about JPG and how it works.  I *knew* it, but never thought about it.  You should've seen me last night scratching my head as paint constantly bled through my images...  I was opening FILE$, blacking out the grays, and then overwtiting FILE$ with the new image...

So basically I was making my JPG into another JPG, and, as you can guess, that didn't work well!   Removing the extension (LEFT$(LEN(FILE$) - 3) and adding "PNG" to convert to lossless graphics made all my troubles go away!

/SIGH...

The obvious things we don't pay attention to, until it's pointed out to us.  ;D

Anywho...  V0.3 is up now, and the coloring should be complete.  (Though I don't have a working printer to test the PRINT option at the moment, and the Save screen needs a prettier makeover.  At least it all appears to be working as intended.)