Implement LZW decoder

InForm/InForm.bi

@@ -10,7 +10,7 @@ $END IF
 $LET INFORM_BI = TRUE
 
 DECLARE LIBRARY
-    FUNCTION __UI_GetPID ALIAS getpid ()
+    FUNCTION __UI_GetPID ALIAS getpid
 END DECLARE
 
 DECLARE CUSTOMTYPE LIBRARY

InForm/UiEditorPreview.bas

@@ -91,8 +91,8 @@ $END IF
 ContextMenuIcon = LoadEditorImage("contextmenu.bmp")
 __UI_ClearColor ContextMenuIcon, 0, 0
 
-'$INCLUDE:'InForm.bi'
 '$INCLUDE:'extensions/GIFPlay.bi'
+'$INCLUDE:'InForm.bi'
 '$INCLUDE:'xp.uitheme'
 '$INCLUDE:'UiEditorPreview.frm'
 
@@ -165,7 +165,7 @@ SUB __UI_BeforeUpdateDisplay
     END IF
 
     FOR i = 1 TO UBOUND(AutoPlayGif)
-        IF AutoPlayGif(i) THEN GIF_Draw i
+        IF AutoPlayGif(i) THEN GIF_Draw i, True
     NEXT
 
     STATIC prevDefaultButton AS LONG, prevMenuPanelActive AS INTEGER
@@ -2218,7 +2218,7 @@ SUB DeleteSelectedControls
             IF __UI_TotalActiveMenus > 0 AND __UI_ParentMenu(__UI_TotalActiveMenus) = Control(i).ID THEN
                 __UI_CloseAllMenus
             END IF
-            GIF_Close i
+            GIF_Free i
             __UI_DestroyControl Control(i)
             IF MustRefreshMenuBar THEN __UI_RefreshMenuBar
             IF MustRefreshContextMenus THEN RefreshContextMenus
@@ -2388,7 +2388,7 @@ SUB LoadPreview (Destination AS _BYTE)
     IF Disk THEN
         FOR i = UBOUND(Control) TO 1 STEP -1
             IF LEFT$(Control(i).Name, 5) <> "__UI_" THEN
-                GIF_Close i
+                GIF_Free i
                 __UI_DestroyControl Control(i)
             END IF
         NEXT
@@ -2407,7 +2407,7 @@ SUB LoadPreview (Destination AS _BYTE)
     ELSEIF UndoBuffer THEN
         FOR i = UBOUND(Control) TO 1 STEP -1
             IF LEFT$(Control(i).Name, 5) <> "__UI_" THEN
-                GIF_Close i
+                GIF_Free i
                 __UI_DestroyControl Control(i)
             END IF
         NEXT
@@ -2764,7 +2764,7 @@ SUB LoadPreview (Destination AS _BYTE)
         IF NOT CorruptedData THEN
             __UI_FirstSelectedID = FirstToBeSelected
         ELSE
-            GIF_Close TempValue
+            GIF_Free TempValue
             __UI_DestroyControl Control(TempValue)
             __UI_TotalSelectedControls = __UI_TotalSelectedControls - 1
         END IF
@@ -2810,7 +2810,7 @@ SUB LoadPreviewText
         __UI_AutoRefresh = False
         FOR i = UBOUND(Control) TO 1 STEP -1
             IF LEFT$(Control(i).Name, 5) <> "__UI_" THEN
-                GIF_Close i
+                GIF_Free i
                 __UI_DestroyControl Control(i)
             END IF
         NEXT
@@ -3062,7 +3062,7 @@ SUB LoadPreviewText
                     DIM RegisterResult AS _BYTE
                     DummyText$ = nextParameter(b$) 'discard first parameter
                     DummyText$ = nextParameter(b$)
-                    RegisterResult = GIF_OpenFile(TempValue, DummyText$)
+                    RegisterResult = GIF_LoadFromFile(TempValue, DummyText$)
                     IF RegisterResult THEN
                         IF LogFileLoad THEN PRINT #LogFileNum, "LOAD SUCCESSFUL"
                         Text(TempValue) = DummyText$ 'indicates image loaded successfully
@@ -3070,7 +3070,7 @@ SUB LoadPreviewText
                             _FREEIMAGE Control(TempValue).HelperCanvas
                         END IF
                         Control(TempValue).HelperCanvas = _NEWIMAGE(GIF_GetWidth(TempValue), GIF_GetHeight(TempValue), 32)
-                        GIF_Draw TempValue
+                        GIF_Draw TempValue, True
                     END IF
                 ELSEIF b$ = "IF __UI_RegisterResult THEN PlayGif __UI_NewID" OR LEFT$(b$, 8) = "PlayGif " THEN
                     IF LogFileLoad THEN PRINT #LogFileNum, "AUTOPLAY GIF"
@@ -3159,11 +3159,11 @@ END SUB
 SUB PreviewLoadImage (This AS __UI_ControlTYPE, fileName$)
     IF LCASE$(RIGHT$(fileName$, 4)) = ".gif" THEN
         DIM tryGif AS _BYTE
-        GIF_Close This.ID
+        GIF_Free This.ID
-        tryGif = GIF_OpenFile(This.ID, fileName$)
+        tryGif = GIF_LoadFromFile(This.ID, fileName$)
         IF tryGif THEN
             IF GIF_GetTotalFrames(This.ID) = 1 THEN
-                GIF_Close This.ID
+                GIF_Free This.ID
             ELSE
                 Text(This.ID) = fileName$ 'indicates image loaded successfully
                 IF This.HelperCanvas < -1 THEN
@@ -3171,12 +3171,12 @@ SUB PreviewLoadImage (This AS __UI_ControlTYPE, fileName$)
                 END IF
                 This.HelperCanvas = _NEWIMAGE(GIF_GetWidth(This.ID), GIF_GetHeight(This.ID), 32)
                 AutoPlayGif(This.ID) = False
-                GIF_Draw This.ID
+                GIF_Draw This.ID, True
                 EXIT SUB
             END IF
         END IF
     END IF
-    GIF_Close This.ID
+    GIF_Free This.ID
     LoadImage This, fileName$
 END SUB
 
@@ -3581,7 +3581,7 @@ SUB SavePreview (Destination AS _BYTE)
                     b$ = MKI$(-44) + MKI$(LEN(RTRIM$(__UI_KeyCombo(Control(i).KeyCombo).FriendlyCombo))) + RTRIM$(__UI_KeyCombo(Control(i).KeyCombo).FriendlyCombo)
                     IF Disk THEN PUT #BinFileNum, , b$ ELSE Clip$ = Clip$ + b$
                 END IF
-                IF GIF_GetIndex(i) > 0 THEN
+                IF GIF_IsLoaded(i) THEN
                     'PictureBox has an animated GIF loaded
                     b$ = MKI$(-45)
                     IF Disk THEN

InForm/extensions/GIFPlay.bas

@@ -8,77 +8,393 @@ $IF GIFPLAY_BAS = UNDEFINED THEN
 
     '$INCLUDE:'GIFPlay.bi'
 
-    FUNCTION GIF_OpenFile%% (Id AS LONG, fileName AS STRING)
+    ' This is an internal loading function common for both memory and file loaders
+    FUNCTION __GIF_Load%% (Id AS LONG, sf AS StringFileType)
+    END FUNCTION
+
+    ' Opens a GIF file from a buffer in memory
+    FUNCTION GIF_LoadFromMemory%% (Id AS LONG, buffer AS STRING)
+        _MESSAGEBOX , "GIF_LoadFromMemory%%"
+
+        DIM sf AS StringFileType
+
+        StringFile_Create sf, buffer
+
+        GIF_LoadFromMemory = __GIF_Load(Id, sf)
     END FUNCTION
 
 
-    FUNCTION GIF_OpenMemory%% (Id AS LONG, buffer AS STRING)
+    ' Opens a GIF file from a file on disk
+    FUNCTION GIF_LoadFromFile%% (Id AS LONG, fileName AS STRING)
+        _MESSAGEBOX STR$(Id), "GIF_LoadFromFile%%"
+
+        DIM sf AS StringFileType
+
+        IF StringFile_Load(sf, fileName) THEN
+            GIF_LoadFromFile = __GIF_Load(Id, sf)
+        END IF
     END FUNCTION
 
 
-    SUB GIF_Close (Id AS LONG)
+    ' Free a GIF and all associated resources
+    SUB GIF_Free (Id AS LONG)
+        _MESSAGEBOX STR$(Id), "GIF_Free"
     END SUB
 
 
-    FUNCTION GIF_GetHeight~% (Id AS LONG)
+    ' Returns the width of the animation in pixels
-    END FUNCTION
-
-
     FUNCTION GIF_GetWidth~% (Id AS LONG)
+        _MESSAGEBOX STR$(Id), "GIF_LoadFromFile%%"
+
+        SHARED __GIFPlayHashTable() AS HashTableType
+        SHARED __GIFPlay() AS __GIFPlayType
+
+        GIF_GetWidth = __GIFPlay(HashTable_LookupLong(__GIFPlayHashTable(), Id)).W
     END FUNCTION
 
 
+    ' Returns the height of the animation in pixels
+    FUNCTION GIF_GetHeight~% (Id AS LONG)
+        _MESSAGEBOX STR$(Id), "GIF_GetHeight~%"
+
+        SHARED __GIFPlayHashTable() AS HashTableType
+        SHARED __GIFPlay() AS __GIFPlayType
+
+        GIF_GetHeight = __GIFPlay(HashTable_LookupLong(__GIFPlayHashTable(), Id)).H
+    END FUNCTION
+
+
+    ' Returns the number of currently playing frame
     FUNCTION GIF_GetCurrentFrame~& (Id AS LONG)
+        _MESSAGEBOX STR$(Id), "GIF_GetCurrentFrame~&"
+
+        SHARED __GIFPlayHashTable() AS HashTableType
+        SHARED __GIFPlay() AS __GIFPlayType
+
+        GIF_GetCurrentFrame = __GIFPlay(HashTable_LookupLong(__GIFPlayHashTable(), Id)).currentFrameNumber
     END FUNCTION
 
 
+    ' Returns the total frames in the GIF. If this is 1 then it is a static image
     FUNCTION GIF_GetTotalFrames~& (Id AS LONG)
+        _MESSAGEBOX STR$(Id), "GIF_GetTotalFrames~&"
+
+        SHARED __GIFPlayHashTable() AS HashTableType
+        SHARED __GIFPlay() AS __GIFPlayType
+
+        GIF_GetTotalFrames = __GIFPlay(HashTable_LookupLong(__GIFPlayHashTable(), Id)).totalFrames
     END FUNCTION
 
 
+    ' Sets the playback direction. direction should be -1 or 1
     SUB GIF_SetPlaybackDirection (Id AS LONG, direction AS _BYTE)
+        _MESSAGEBOX STR$(Id), "GIF_SetPlaybackDirection"
+
+        SHARED __GIFPlayHashTable() AS HashTableType
+        SHARED __GIFPlay() AS __GIFPlayType
+
+        IF direction <> 0 THEN __GIFPlay(HashTable_LookupLong(__GIFPlayHashTable(), Id)).direction = SGN(direction)
     END SUB
 
 
+    ' Gets the current playback direction. This can be -1 or 1
     FUNCTION GIF_GetPlaybackDirection%% (Id AS LONG)
+        _MESSAGEBOX STR$(Id), "GIF_GetPlaybackDirection%%"
+
+        SHARED __GIFPlayHashTable() AS HashTableType
+        SHARED __GIFPlay() AS __GIFPlayType
+
+        GIF_GetPlaybackDirection = __GIFPlay(HashTable_LookupLong(__GIFPlayHashTable(), Id)).direction
     END FUNCTION
 
 
+    ' Resume or starts playback
     SUB GIF_Play (Id AS LONG)
+        _MESSAGEBOX STR$(Id), "GIF_Play"
+
+        SHARED __GIFPlayHashTable() AS HashTableType
+        SHARED __GIFPlay() AS __GIFPlayType
+
+        __GIFPlay(HashTable_LookupLong(__GIFPlayHashTable(), Id)).isPlaying = TRUE
     END SUB
 
 
+    ' Pauses playback. That same frame is served as long as playback is paused
     SUB GIF_Pause (Id AS LONG)
+        _MESSAGEBOX STR$(Id), "GIF_Pause"
+
+        SHARED __GIFPlayHashTable() AS HashTableType
+        SHARED __GIFPlay() AS __GIFPlayType
+
+        __GIFPlay(HashTable_LookupLong(__GIFPlayHashTable(), Id)).isPlaying = FALSE
     END SUB
 
 
+    ' Stops playing the GIF and resets the cursor to the first frame
     SUB GIF_Stop (Id AS LONG)
+        _MESSAGEBOX STR$(Id), "GIF_Stop"
+
+        SHARED __GIFPlayHashTable() AS HashTableType
+        SHARED __GIFPlay() AS __GIFPlayType
+
+        DIM idx AS LONG: idx = HashTable_LookupLong(__GIFPlayHashTable(), Id)
+
+        __GIFPlay(idx).isPlaying = FALSE
+        __GIFPlay(idx).currentFrame = __GIFPlay(idx).firstFrame
     END SUB
 
 
+    ' Return True if GIF is currently playing
     FUNCTION GIF_IsPlaying%% (Id AS LONG)
+        _MESSAGEBOX STR$(Id), "GIF_IsPlaying%%"
+
+        SHARED __GIFPlayHashTable() AS HashTableType
+        SHARED __GIFPlay() AS __GIFPlayType
+
+        GIF_IsPlaying = __GIFPlay(HashTable_LookupLong(__GIFPlayHashTable(), Id)).isPlaying
     END FUNCTION
 
 
-    SUB GIF_Draw (Id AS LONG)
+    ' This draws the current frame on the destination surface @ (0, 0) (stretching the frame if needed)
+    ' This will also draw the overlay if the playback is stopped / paused
+    SUB GIF_Draw (Id AS LONG, shouldStretch AS _BYTE)
+        ' TODO
     END SUB
 
 
-    SUB GIF_DrawPro (Id AS LONG, x AS LONG, y AS LONG)
+    ' This draws the current frame at the specified x, y location on the destination surface (preserving aspect ratio)
+    ' This will also draw the overlay if the playback is stopped / paused
+    SUB GIF_DrawAt (Id AS LONG, x AS LONG, y AS LONG)
+        _MESSAGEBOX STR$(Id), "GIF_DrawAt"
     END SUB
 
 
+    ' This returns the current frame (QB64 image) to be played
+    ' Playback is time sensitive so frames may be skipped or the last frame maybe returned
+    ' Only use this if you want to do your own rendering
+    ' Also do not free the image. The library will do that when it is no longer needed
     FUNCTION GIF_GetFrame& (Id AS LONG)
+        _MESSAGEBOX STR$(Id), "GIF_GetFrame&"
     END FUNCTION
 
 
+    ' Sets the GIF overlay to enable / disable
     SUB GIF_EnableOverlay (Id AS LONG, isEnabled AS _BYTE)
+        _MESSAGEBOX STR$(Id), "GIF_EnableOverlay"
+
+        SHARED __GIFPlayHashTable() AS HashTableType
+        SHARED __GIFPlay() AS __GIFPlayType
+
+        __GIFPlay(HashTable_LookupLong(__GIFPlayHashTable(), Id)).overlayEnabled = isEnabled
     END SUB
 
 
-    ' Returns the __GIFPlay index of a loaded GIF using it's ID
+    ' Returns TRUE if a GIF with Id is loaded
-    ' TODO: Fix line in UiEditorPreview: IF GIF_GetIndex(i) > 0 THEN
+    FUNCTION GIF_IsLoaded%% (Id AS LONG)
-    FUNCTION GIF_GetIndex~& (Id AS LONG)
+        SHARED __GIFPlayHashTable() AS HashTableType
+
+        GIF_IsLoaded = HashTable_IsKeyPresent(__GIFPlayHashTable(), Id)
+    END FUNCTION
+
+
+    SUB __GIF_CreateBitmap (bmp AS __GIFBitmapType, w AS LONG, h AS LONG)
+        bmp.W = w
+        bmp.H = h
+        bmp.pixels = STRING$(w * h, 0)
+    END SUB
+
+
+    SUB __GIF_BlitBitmap (src AS __GIFBitmapType, dst AS __GIFBitmapType, srcX AS LONG, srcY AS LONG, dstX AS LONG, dstY AS LONG, bW AS LONG, bH AS LONG)
+        IF bW <= 0 OR bH <= 0 THEN EXIT SUB
+
+        DIM AS LONG w, xs, xd: w = bW: xs = srcX: xd = dstX
+        DIM AS LONG h, ys, yd: h = bH: ys = srcY: yd = dstY
+
+        IF xs < 0 THEN
+            w = w + xs
+            xd = xd - xs
+            xs = 0
+        END IF
+        IF ys < 0 THEN
+            h = h + ys
+            yd = yd - ys
+            ys = 0
+        END IF
+
+        IF xs + w > src.W THEN w = src.W - xs
+        IF ys + h > src.H THEN h = src.H - ys
+
+        IF xd < 0 THEN
+            w = w + xd
+            xs = xs - xd
+            xd = 0
+        END IF
+        IF yd < 0 THEN
+            h = h + yd
+            ys = ys - yd
+            yd = 0
+        END IF
+
+        IF xd + w > dst.W THEN w = dst.W - xd
+        IF yd + h > dst.H THEN h = dst.H - yd
+
+        IF w <= 0 OR h <= 0 THEN EXIT SUB
+
+        DIM ps AS LONG: ps = 1 + ys * src.W
+        DIM pd AS LONG: pd = 1 + yd * dst.W
+        DIM i AS LONG: FOR i = 1 TO h
+            MID$(dst.pixels, pd + xd, w) = MID$(src.pixels, ps + xs, w)
+            ps = ps + src.W
+            pd = pd + dst.W
+        NEXT i
+    END SUB
+
+
+    FUNCTION __GIF_ReadLZWCode& (sf AS StringFileType, buffer AS STRING, bitPos AS LONG, bitSize AS LONG)
+        DIM code AS LONG, p AS LONG: p = 1
+
+        DIM i AS LONG: FOR i = 1 TO bitSize
+            DIM bytePos AS LONG: bytePos = _SHR(bitPos, 3) AND 255
+
+            IF bytePos = 0 THEN
+                DIM dataLen AS LONG: dataLen = StringFile_ReadByte(sf)
+
+                IF dataLen = 0 THEN
+                    __GIF_ReadLZWCode = -1
+                    EXIT FUNCTION
+                END IF
+
+                MID$(buffer, 257 - dataLen) = StringFile_ReadString(sf, dataLen)
+
+                bytePos = 256 - dataLen
+                bitPos = _SHL(bytePos, 3)
+            END IF
+
+            IF ASC(buffer, 1 + bytePos) AND _SHL(1, (bitPos AND 7)) THEN code = code + p
+
+            p = p + p
+            bitPos = bitPos + 1
+        NEXT i
+
+        __GIF_ReadLZWCode = code
+    END FUNCTION
+
+
+    FUNCTION __GIF_DecodeLZW& (sf AS StringFileType, bmp AS __GIFBitmapType)
+        TYPE __LZWCodeType
+            prefix AS LONG
+            c AS LONG
+            ln AS LONG
+        END TYPE
+
+        DIM codes(0 TO 4095) AS __LZWCodeType
+
+        DIM origBitSize AS LONG: origBitSize = StringFile_ReadByte(sf)
+        DIM n AS LONG: n = 2 + _SHL(1, origBitSize)
+
+        DIM i AS LONG: WHILE i < n
+            codes(i).c = i
+            codes(i).ln = 0
+            i = i + 1
+        WEND
+
+        DIM clearMarker AS LONG: clearMarker = n - 2
+        DIM endMarker AS LONG: endMarker = n - 1
+
+        DIM buffer AS STRING: buffer = SPACE$(256)
+        DIM bitSize AS LONG: bitSize = origBitSize + 1
+        DIM bitPos AS LONG
+
+        DIM prev AS LONG: prev = __GIF_ReadLZWCode(sf, buffer, bitPos, bitSize)
+        IF prev = -1 THEN
+            __GIF_DecodeLZW = -1
+            EXIT FUNCTION
+        END IF
+
+        DO
+            DIM code AS LONG: code = __GIF_ReadLZWCode(sf, buffer, bitPos, bitSize)
+            IF code = -1 THEN
+                __GIF_DecodeLZW = -1
+                EXIT FUNCTION
+            END IF
+
+            IF code = clearMarker THEN
+                bitSize = origBitSize
+                n = _SHL(1, bitSize)
+                n = n + 2
+                bitSize = bitSize + 1
+                prev = code
+                _CONTINUE
+            END IF
+
+            IF code = endMarker THEN EXIT DO
+
+            DIM c AS LONG: IF code < n THEN c = code ELSE c = prev
+
+            DIM outPos AS LONG: outPos = outPos + codes(c).ln
+            i = 0
+
+            DO
+                ASC(bmp.pixels, 1 + outPos - i) = codes(c).c
+
+                IF codes(c).ln THEN
+                    c = codes(c).prefix
+                ELSE
+                    EXIT DO
+                END IF
+
+                i = i + 1
+            LOOP
+
+            outPos = outPos + 1
+
+            IF code >= n THEN
+                ASC(bmp.pixels, 1 + outPos) = codes(c).c
+                outPos = outPos + 1
+            END IF
+
+            IF prev <> clearMarker THEN
+                codes(n).prefix = prev
+                codes(n).ln = codes(prev).ln + 1
+                codes(n).c = codes(c).c
+                n = n + 1
+            END IF
+
+            IF _SHL(1, bitSize) = n THEN
+                IF bitSize < 12 THEN bitSize = bitSize + 1
+            END IF
+
+            prev = code
+        LOOP
+    END FUNCTION
+
+
+    ' This load the GIF overload image
+    FUNCTION __GIF_LoadOverlayImage&
+        CONST SIZE_GIFOVERLAYIMAGE_BMP_16506 = 16506
+        CONST COMP_GIFOVERLAYIMAGE_BMP_16506 = -1
+        CONST DATA_GIFOVERLAYIMAGE_BMP_16506 = _
+            "eNpy8q1yYACDKiDOAWIHKGZkUGBgZsAF/kMQjDM4gRSgfbsGjt+I4jgexj+2YU57nd27H0Nl6htD6wkzJ31hqFyFWkMVZmZm5rzjMyjfzcwLvEKj" + _
+            "tXTnFbyZjxn0O60WBBjDdVjDU/gAP0LwK77CW3gKa7gOY+B3c1k13Ic3ICm9gftQQ8h1BIt4GdInL2MRRxBKHcd1+BIyIF/iehzHYdWpmMXnkEPy" + _
+            "OWZxKgZZV2AbEohtXI5B1Di+hQTmW4z3ub3fBQncXX04Hs7CKiQnVnFWhtkfh+TM4zgrgza/AsmplZTHwh2QnLszRT8vheA/LlyObyAF8Q0u9zjm" + _
+            "tyEFs52wL5iFFNRsgrXMZ5CC+gwnY/JfBym462LW719BCu4rHIGtRUhJLNo+H29ASuINMxYMQ1JooIUOekYHLTQgFpromJ8V1NFGV7+HOiQjw9C6" + _
+            "L0VumzlOB02TvWehhTZ6VoavwX3QehXixWz7ysrK7rPPPrsXmXJfc98zGdqoa8bNzc2/f++tt97a19dJ9/tPP/20H1EPPfSQ/o0mJAOvwdVFabK7" + _
+            "bFHCeuSRR/ZMWxh4fuMiTBygzff+u9267XY/X3vttT33Nc3gyn08NTW1474fQP4J3ATx0LH7/eabbzbt24D7mUajEWmWQPLfhHXffT8yMrJjs6Nr" + _
+            "+3k00LZZAsq/jqcgCbX+u+8/++yzfc2OOgR1bSNWgPmfwoe+bd/ljig93tGCOLrd/ctvwM4dPLyL7yAJ9Rxt+/Pz8ztmnzTRc1+PYirT/Ibna/AF" + _
+            "5KD56Qc0f72v+ROU+V1J6JeM89v2Hy+A/Inav8mm45ht/7b/i9FBPZD2n0X/107ye0YnhP4vzfjnti3BuqShc0FdC7iPQxn/fOc/msX2ZTr/Qd2u" + _
+            "be2cIaD5/3oW81/tByzl5vsRZecM2R//3ucJbsLYQdc/bnv/u8616wCX2635Isrse6eRYX6r67H+uRDiqYWeo/mSjE8cN6aPzm78i5mTxbkIrl5J" + _
+            "8xroOlfHBbvmN+2iAwkg/6vQuhfixfRvCWj/KN7nv/x1Pc9/DfX5/GcD9ZTnP5Fp/zdkzn+/Xsrz39X1D63z8SWk4L7Eker6Z2mvfx9HXM2U+P4H" + _
+            "HQu2IAVDJrIlq8uKd/8TmfxqrMT3v2ndBsm526v7X6v7n6v736vnH6rnX6rnnzI+HmYCeP5tBqeW8PnH63A8wOdfX4L0yUvm+ddQq4a78QokpVdw" + _
+            "N2rIY+nz70tYxZN431x3/g7v40msYmlQz7//BcxY2A4="
+
+        STATIC overlayImage AS LONG
+
+        ' Only do this once
+        IF overlayImage = 0 THEN
+            overlayImage = _LOADIMAGE(Base64_LoadResourceString(DATA_GIFOVERLAYIMAGE_BMP_16506, SIZE_GIFOVERLAYIMAGE_BMP_16506, COMP_GIFOVERLAYIMAGE_BMP_16506), 32, "memory")
+        END IF
+
+        __GIF_LoadOverlayImage = overlayImage
     END FUNCTION
 
     '$INCLUDE:'HashTable.bas'

InForm/extensions/GIFPlay.bi

@@ -6,41 +6,55 @@
 $IF GIFPLAY_BI = UNDEFINED THEN
     $LET GIFPLAY_BI = TRUE
 
-    $IF INFORM_BI = UNDEFINED THEN
+    ' TODO: remove this once done
-        DEFLNG A-Z
+    '$IF INFORM_BI = UNDEFINED THEN
-        OPTION _EXPLICIT
+    '    DEFLNG A-Z
+    '    OPTION _EXPLICIT
 
-        CONST FALSE = 0, TRUE = NOT FALSE
+    '    CONST FALSE = 0, TRUE = NOT FALSE
-    $END IF
+    '$END IF
 
     '$INCLUDE:'HashTable.bi'
     '$INCLUDE:'StringFile.bi'
 
+    ' This is the master GIF type that holds info about a single GIF file
     TYPE __GIFPlayType
-        id AS LONG ' handle supplied by the user (do we need this?)
         W AS _UNSIGNED INTEGER ' GIF global width (this needs to be 16-bit)
         H AS _UNSIGNED INTEGER ' GIF global height (this needs to be 16-bit)
         bgColor AS _UNSIGNED _BYTE ' background color
+        colors AS _UNSIGNED INTEGER ' total colors in the global palette
         pal AS STRING * 768 ' global palette - 256 colors * 3 components
-        frame AS LONG ' index of the first frame in the frame data array
+        firstFrame AS LONG ' index of the first frame in the frame data array
-        frames AS LONG ' total frames in the animation
+        currentFrame AS LONG ' index of the current frame being played
-        hideOverlay AS _BYTE ' should the "GIF" overlay be hidden when it is not playing
+        totalFrames AS LONG ' total number of frames counted while loading
+        currentFrameNumber AS LONG ' this is simply the number of current frame since playback (re)started
+        isPlaying AS _BYTE ' set to true if the GIF is currently playing
+        direction AS _BYTE ' playback direction (-1 or +1)
+        overlayEnabled AS _BYTE ' should the "GIF" overlay be shown / hidden when it is not playing
     END TYPE
 
+    ' This is the a GIF frame type that holds info about an individual GIF frame
     TYPE __GIFPlayFrameType
-        id AS LONG ' which GIF handle does this belong to?
+        id AS LONG ' index to __GIFPlay that this frame belongs to (do we really need this?)
         image AS LONG ' QB64 image handle
         L AS _UNSIGNED INTEGER ' frame left (this needs to be 16-bit) (do we need these?)
         T AS _UNSIGNED INTEGER ' frame top (this needs to be 16-bit)
         W AS _UNSIGNED INTEGER ' frame width (this needs to be 16-bit)
         H AS _UNSIGNED INTEGER ' frame height (this needs to be 16-bit)
-        pre AS LONG ' previous frame (this will link back to the last frame if this is the first one)
+        prevFrame AS LONG ' previous frame (this will link back to the last frame if this is the first one)
-        nxt AS LONG ' next frame (this will link back to the first frame if this is the last one)
+        nextFrame AS LONG ' next frame (this will link back to the first frame if this is the last one)
-        delayMs AS SINGLE ' frame delay time
+        timeMs AS SINGLE ' frame time
-        direction AS _BYTE ' playback direction
     END TYPE
 
-    REDIM __GIFPlayHashTable(0 TO 0) AS HashTableType
+    ' This is used by temporary variables during the decoding step to store the raw data for a single frame
-    REDIM __GIFPlay(0 TO 0) AS __GIFPlayType
+    TYPE __GIFBitmapType
-    REDIM __GIFPlayFrame(0 TO 0) AS __GIFPlayFrameType
+        W AS LONG
+        H AS LONG
+        pixels AS STRING
+    END TYPE
+
+    REDIM __GIFPlayHashTable(0 TO 0) AS HashTableType ' shared hash table to keep user supplied IDs (the values here points to indexes in __GIFPlay)
+    REDIM __GIFPlay(0 TO 0) AS __GIFPlayType ' main GIFPlay array - each array element is for a single GIF
+    REDIM __GIFPlayFrame(0 TO 0) AS __GIFPlayFrameType ' shared GIF frame array - this holds GIF frame and frame information for all loaded GIFs
+
 $END IF

InForm/extensions/HashTable.bas

@@ -90,25 +90,33 @@ $IF HASHTABLE_BAS = UNDEFINED THEN
     'PRINT "Value for key 7:"; HashTable_LookupLong(MyHashTable(), 7)
     'PRINT "Value for key 21:"; HashTable_LookupLong(MyHashTable(), 21)
 
+    'PRINT HashTable_IsKeyPresent(MyHashTable(), 100)
+
     'END
     '-------------------------------------------------------------------------------------------------------------------
 
     ' Simple hash function: k is the 32-bit key and l is the upper bound of the array
     FUNCTION __HashTable_GetHash~& (k AS _UNSIGNED LONG, l AS _UNSIGNED LONG)
-        __HashTable_GetHash = k MOD (l + 1) ' + 1 is needed for 0 based arrays
+        $CHECKING:OFF
+        ' Actually this should be k MOD (l + 1)
+        ' However, we can get away using AND because our arrays size always doubles in multiples of 2
+        ' So, if l = 255, then (k MOD (l + 1)) = (k AND l)
+        ' Another nice thing here is that we do not need to do the addition :)
+        __HashTable_GetHash = k AND l
+        $CHECKING:ON
     END FUNCTION
 
 
     ' Subroutine to resize and rehash the elements in a hash table
     SUB __HashTable_ResizeAndRehash (hashTable() AS HashTableType)
-        DIM UB AS _UNSIGNED LONG: UB = UBOUND(hashTable)
+        DIM uB AS _UNSIGNED LONG: uB = UBOUND(hashTable)
 
         ' Resize the array to double its size while preserving contents
-        DIM newUB AS _UNSIGNED LONG: newUB = _SHL(UB + 1, 1) - 1
+        DIM newUB AS _UNSIGNED LONG: newUB = _SHL(uB + 1, 1) - 1
         REDIM _PRESERVE hashTable(0 TO newUB) AS HashTableType
 
         ' Rehash and swap all the elements
-        DIM i AS _UNSIGNED LONG: FOR i = 0 TO UB
+        DIM i AS _UNSIGNED LONG: FOR i = 0 TO uB
             IF hashTable(i).U THEN SWAP hashTable(i), hashTable(__HashTable_GetHash(hashTable(i).K, newUB))
         NEXT i
     END SUB
@@ -117,8 +125,8 @@ $IF HASHTABLE_BAS = UNDEFINED THEN
     ' This returns an array index in hashTable where k can be inserted
     ' If there is a collision it will grow the array, re-hash and copy all elements
     FUNCTION __HashTable_GetInsertIndex& (hashTable() AS HashTableType, k AS _UNSIGNED LONG)
-        DIM ub AS _UNSIGNED LONG: ub = UBOUND(hashTable)
+        DIM uB AS _UNSIGNED LONG: uB = UBOUND(hashTable)
-        DIM idx AS _UNSIGNED LONG: idx = __HashTable_GetHash(k, ub)
+        DIM idx AS _UNSIGNED LONG: idx = __HashTable_GetHash(k, uB)
 
         IF hashTable(idx).U THEN
             ' Used slot
@@ -139,8 +147,8 @@ $IF HASHTABLE_BAS = UNDEFINED THEN
 
     ' This function returns the index from hashTable for the key k if k is in use
     FUNCTION __HashTable_GetLookupIndex& (hashTable() AS HashTableType, k AS _UNSIGNED LONG)
-        DIM ub AS _UNSIGNED LONG: ub = UBOUND(hashTable)
+        DIM uB AS _UNSIGNED LONG: uB = UBOUND(hashTable)
-        DIM idx AS _UNSIGNED LONG: idx = __HashTable_GetHash(k, ub)
+        DIM idx AS _UNSIGNED LONG: idx = __HashTable_GetHash(k, uB)
 
         IF hashTable(idx).U THEN
             ' Used slot
@@ -158,6 +166,12 @@ $IF HASHTABLE_BAS = UNDEFINED THEN
     END FUNCTION
 
 
+    ' Return TRUE if k is available in the hash table
+    FUNCTION HashTable_IsKeyPresent%% (hashTable() AS HashTableType, k AS _UNSIGNED LONG)
+        HashTable_IsKeyPresent = (__HashTable_GetLookupIndex(hashTable(), k) >= 0)
+    END FUNCTION
+
+
     ' Remove an element from the hash table
     SUB HashTable_Remove (hashTable() AS HashTableType, k AS _UNSIGNED LONG)
         DIM idx AS LONG: idx = __HashTable_GetLookupIndex(hashTable(), k)

InForm/extensions/HashTable.bi

@@ -6,23 +6,16 @@
 $IF HASHTABLE_BI = UNDEFINED THEN
     $LET HASHTABLE_BI = TRUE
 
-    $IF INFORM_BI = UNDEFINED THEN
-        DEFLNG A-Z
-        OPTION _EXPLICIT
-
-        CONST FALSE = 0, TRUE = NOT FALSE
-    $END IF
-
     CONST __HASHTABLE_KEY_EXISTS = -1
     CONST __HASHTABLE_KEY_UNAVAILABLE = -2
 
     ' Hash table entry type
+    ' To extended supported data types, add other value types after V and then write
+    ' wrappers around __HashTable_GetInsertIndex() & __HashTable_GetLookupIndex()
     TYPE HashTableType
         U AS _BYTE ' used?
         K AS _UNSIGNED LONG ' key
         V AS LONG ' value
-        ' <- add other value types here and then write wrappers
-        ' around __HashTable_GetInsertIndex() & __HashTable_GetLookupIndex()
     END TYPE
 
 $END IF

InForm/extensions/Ini.bi

@@ -7,13 +7,6 @@
 $IF INI_BI = UNDEFINED THEN
     $LET INI_BI = TRUE
 
-    $IF INFORM_BI = UNDEFINED THEN
-        DEFLNG A-Z
-        OPTION _EXPLICIT
-
-        CONST FALSE = 0, TRUE = NOT FALSE
-    $END IF
-
     ' TODO:
     ' We should put all of this stuff into a single state type and then have just a single global to avoid possible name collisions.
     ' INI routines without namespace like prefix should also be prefixed with the "Ini_" prefix

InForm/extensions/MessageBox.bi

@@ -6,13 +6,6 @@
 $IF MESSAGEBOX_BI = UNDEFINED THEN
     $LET MESSAGEBOX_BI = TRUE
 
-    $IF INFORM_BI = UNDEFINED THEN
-        DEFLNG A-Z
-        OPTION _EXPLICIT
-
-        CONST FALSE = 0, TRUE = NOT FALSE
-    $END IF
-
     'Messagebox constants
     CONST MsgBox_OkOnly = 1
     CONST MsgBox_OkCancel = 2

InForm/extensions/StringFile.bi

@@ -6,13 +6,6 @@
 $IF STRINGFILE_BI = UNDEFINED THEN
     $LET STRINGFILE_BI = TRUE
 
-    $IF INFORM_BI = UNDEFINED THEN
-        DEFLNG A-Z
-        OPTION _EXPLICIT
-
-        CONST FALSE = 0, TRUE = NOT FALSE
-    $END IF
-
     ' Simplified QB64-only memory-file
     TYPE StringFileType
         buffer AS STRING

examples/GIFPlaySample/GIFPlaySample.bas

@@ -14,8 +14,8 @@ DIM SHARED LoadBT AS LONG
 DIM SHARED PlayBT AS LONG
 
 ': External modules: ---------------------------------------------------------------
-'$INCLUDE:'../../InForm/InForm.bi'
 '$INCLUDE:'../../InForm/extensions/GIFPlay.bi'
+'$INCLUDE:'../../InForm/InForm.bi'
 '$INCLUDE:'../../InForm/extensions/MessageBox.bi'
 '$INCLUDE:'GIFPlaySample.frm'
 
@@ -28,7 +28,7 @@ SUB __UI_OnLoad
 END SUB
 
 SUB __UI_BeforeUpdateDisplay
-    GIF_Update PictureBox1
+    GIF_Draw PictureBox1, True
 END SUB
 
 SUB __UI_BeforeUnload
@@ -42,7 +42,7 @@ SUB __UI_Click (id AS LONG)
             DIM fileName AS STRING: fileName = _OPENFILEDIALOG$(Caption(gifplaySample), , "*.gif|*.GIF|*.Gif", "GIF Files")
 
             IF LEN(fileName) > 0 THEN
-                IF GIF_Open(PictureBox1, fileName) THEN
+                IF GIF_LoadFromFile(PictureBox1, fileName) THEN
 
                     Control(PlayBT).Disabled = False
 
@@ -67,7 +67,7 @@ SUB __UI_Click (id AS LONG)
             END IF
 
         CASE PictureBox1
-            GIF_HideOverlay PictureBox1
+            GIF_EnableOverlay PictureBox1, False
     END SELECT
 END SUB