Add PNG reading ability

Also increased the minimum work area of the uutput window so the up/down adjusters don't get squashed with very small images.

Tested with 174 test PNGs from the PNG test suite.

Version 1.43. Tagged as 'ChangeFSI-1_43'

DataFiles/Documents/Formats

@@ -63,6 +63,8 @@ Alpiar 36 bit per pixel
 Alpiar 48 bit per pixel
 Kodak RGB images, 24 bits per pixel
 BTPC 4.1 images 
+Portable network graphics 1, 2, 4, 8, 16, 24, 48 bits per pixel
+   interlaced or non interlaced image ordering
 
 Output formats
 --------------
@@ -666,6 +668,19 @@ BTPC 4.1 images
   Binary tree predictive coding is used to achieve a signal to noise ratio
   better than that achieved with a JPEG algorithm, and in less time too.
 
+Portable network graphics
+-------------------------
+ Recognised by unique 8 byte signature at the start of the file.
+   
+ The reader is based on the PNG 1.2 specification, and supports all of
+  the critical chunks described in the specification. All defined filter types
+  and interlacing schemes are also supported.
+
+ The ancilliary chunks, such as gamma correction and histogram, are ignored
+  as on the whole ChangeFSI already has a means to manipulate these parameters.
+  Some chunks are for information only (such as the various supplementary text
+  and date stamp information).
+
 Table summarising the formats
 =============================
 
@@ -720,3 +735,4 @@ Alpiar 36 bit per pixel                       [ALPIAR12 at start of file]
 Alpiar 48 bit per pixel                       [ALPIAR16 at start of file]
 Kodak RGB images, 24 bits per pixel           [named /RGB]
 BTPC file                                     [bptc at start of file]
+Portable network graphics                     [8 byte signature at start of file]

DataFiles/Documents/Theory

@@ -530,7 +530,7 @@ Adding a new format is a matter of:
  Reading the size of the image and the colour palette mapping in the next
   section of the program.
 
- Writing a "read pixel row" element inside PROCiprow.
+ Writing a "read pixel row" FN named in r$ and called from PROCreadpixelrow.
 
  Providing an entry in PROCrewind.
 

Makefile

@@ -41,7 +41,6 @@ LDIR       = ${LOCALE}
 SDIR       = source
 CFSIDIR    = ${INSTDIR}.${APP}
 VPATH      = @ JPEG6b hpcdtoppm btpc
-MSGVERSION = ${AWK} -f Build:AwkVers
 MSGS       = ${DDIR}.Messages
 
 include StdTools
@@ -90,6 +89,7 @@ FILES  =\
  ${DDIR}.djpeg.HourOff\
  ${DDIR}.djpeg.!Run\
  ${DDIR}.ChangeFSI\
+ ${DDIR}.CFSIpng\
  ${DDIR}.cjpeg \
  ${DDIR}.JPEGprint.!Run \
  ${DDIR}.JPEGprint.JPEGprint
@@ -200,7 +200,7 @@ all: ${FILES}
          @${ECHO} ${COMPONENT}: all built
 
 #
-# Note that CFSIjpeg {required} comes as a byproduct of the SprExtend component
+# Note that CFSIjpeg (required) comes as a byproduct of the SprExtend component
 #
 install: ${FILES}
          Set Alias$CPFD ${CP} %0.%1 ${CFSIDIR}.%1 ${CPFLAGS}
@@ -241,6 +241,7 @@ install: ${FILES}
          CPFDL ${LDIR} Templates
          CPFDL ${LDIR} Template3D
          CPFDL ${DDIR} ChangeFSI
+         CPFDL ${DDIR} CFSIpng
          CPFDL ${DDIR} cjpeg
          ${MKDIR} ${CFSIDIR}.btpc
          CPFDL ${DDIR} btpc.btpc
@@ -262,15 +263,14 @@ install: ${FILES}
          @${ECHO} ${COMPONENT}: installed
 
 clean:
-         ${RM} ${DDIR}.ChangeFSI
-         ${RM} ${DDIR}.JPEGprint.JPEGprint
-         ${RM} ${DDIR}.btpc.btpc
-         ${RM} ${DDIR}.DJpeg.DJpeg
-         ${RM} ${DDIR}.CJpeg
-         ${RM} CJpeg
-         ${RM} DJpeg
          ${RM} ${DDIR}.hpcdtoppm
          ${RM} ${MSGS}
+         ${RM} ${DDIR}.ChangeFSI
+         ${RM} ${DDIR}.CFSIpng
+         ${RM} ${DDIR}.cjpeg
+         ${RM} ${DDIR}.btpc.btpc
+         ${RM} ${DDIR}.djpeg.djpeg
+         ${RM} ${DDIR}.JPEGprint.JPEGprint
          ${XWIPE} n   ${WFLAGS}
          ${XWIPE} o.* ${WFLAGS}
          @${ECHO} ${COMPONENT}: cleaned
@@ -317,10 +317,17 @@ ${DDIR}.btpc.btpc: ${BOBJS} ${C++LIB} ${CLIB}
         ${LD} -c++ -o $@ ${BOBJS} ${C++LIB} ${CLIB} 
         ${SQZ} $@
 
+#------------------------------------------------------------------------------
+# CFSIPNG
+#------------------------------------------------------------------------------
+${DDIR}.CFSIPNG: ${SDIR}.CFSI-PNG
+        ${AS} ${ASFLAGS} -o CFSIpng.o ${SDIR}.CFSI-PNG
+        ${LD} -bin -o $@ CFSIpng.o
+
 #------------------------------------------------------------------------------
 # MESSAGES
 #------------------------------------------------------------------------------
 ${MSGS}: ${LDIR}.Messages VersionNum
-        ${MSGVERSION} ${LDIR}.Messages > $@
+        ${INSERTVERSION} ${LDIR}.Messages > $@
 
 # Dynamic dependencies:

VersionNum

-/* (1.42)
+/* (1.43)
  *
  * This file is automatically maintained by srccommit, do not edit manually.
  * Last processed by srccommit version: 1.1.
  *
  */
-#define Module_MajorVersion_CMHG        1.42
+#define Module_MajorVersion_CMHG        1.43
 #define Module_MinorVersion_CMHG        
 #define Module_Date_CMHG                08 Jan 2014
 
-#define Module_MajorVersion             "1.42"
-#define Module_Version                  142
+#define Module_MajorVersion             "1.43"
+#define Module_Version                  143
 #define Module_MinorVersion             ""
 #define Module_Date                     "08 Jan 2014"
 
@@ -18,6 +18,6 @@
 #define Module_ComponentName            "ChangeFSI"
 #define Module_ComponentPath            "mixed/RiscOS/Sources/Apps/ChangeFSI"
 
-#define Module_FullVersion              "1.42"
-#define Module_HelpVersion              "1.42 (08 Jan 2014)"
-#define Module_LibraryVersionInfo       "1:42"
+#define Module_FullVersion              "1.43"
+#define Module_HelpVersion              "1.43 (08 Jan 2014)"
+#define Module_LibraryVersionInfo       "1:43"

source/ChangeFSI

@@ -1788,6 +1788,7 @@ DEF FNChangeFSI(A$,spritearea%,workspace%,worklimit%,oksave%,okinfo%,RETURN ram%
     IF flag=-1 IF LEFT$(S$,4)="FORM" IF MID$(S$,9,4)="ILBM" flag=1600
     IF flag=-1 IF LEFT$(S$,8)="ALPIAR12" flag=3900:colourindex=4095
     IF flag=-1 IF LEFT$(S$,8)="ALPIAR16" flag=3905:colourindex=65535
+    IF flag=-1 IF LEFT$(S$,8)=CHR$&89+"PNG"+CHR$13+CHR$10+CHR$26+CHR$10 flag=4000
     IF flag=-1 THEN
       IF MID$(S$,7,4)="JFIF" OR LEFT$(S$,3)=CHR$&FF+CHR$&D8+CHR$&FF OR ftype=&C85 THEN
         REM Read the cache size variable
@@ -4059,6 +4060,124 @@ DEF FNChangeFSI(A$,spritearea%,workspace%,worklimit%,oksave%,okinfo%,RETURN ram%
       gbo%=2
       bbo%=4
       info$="Ronald Alpiar format, "+ STR$sx%+" by "+ STR$sy%+" pixels, 48 bits per pixel"
+    WHEN 4000
+      REM Portable network graphics (PNG)
+      PTR#c%=8
+      A%=OPENIN"<ChangeFSI$Dir>.CFSIpng"
+      IF A%=0 THEN ERROR 42,"Can't load PNG support code"
+      png%=FNdim(EXT#A%)
+      SYS 12,4,A%,png%,EXT#A%
+      CLOSE#A%
+      SYS "XOS_CLI","rmensure ZLib 0 rmload System:Modules.ZLib"
+      OSCLI"rmensure ZLib 0 ERROR ChangeFSI requires the ZLib module to perform this operation"
+      png1st%=0:REM File PTR of 1st IDAT
+      T%=0:REM Tag order checking has seen nothing
+      V%=TRUE:REM Validity starts OK
+      REPEAT
+        L%=FNbeW:t$=CHR$BGET#c%+CHR$BGET#c%+CHR$BGET#c%+CHR$BGET#c%
+        CASE t$ OF
+          WHEN"IHDR"
+            IF T%<>0 THEN V%=FALSE ELSE T%=T% OR1:REM Only once, must come first
+            sx%=FNbeW
+            sy%=FNbeW
+            PNGdep%=BGET#c%:REM Bit depth
+            PNGcol%=BGET#c%:REM Type 0 is greyscale 1/2/4/8/16bpp
+                            REM Type 2 is 24/48bpp RGB
+                            REM Type 3 is paletted 1,2,4,8bpp
+                            REM Type 4 is 8/16bpp greyscale + alpha
+                            REM Type 6 is 24/48bpp RGB + alpha
+            PNGcmp%=BGET#c%:PNGflt%=BGET#c%:PNGint%=BGET#c%:REM Compressor, filter, interlacing
+            C%=FNbeW:REM Skip CRC32
+          WHEN"PLTE"
+            IF (T% AND15)<>1 THEN V%=FALSE ELSE T%=T% OR2:REM Only once, before IDAT, before IEND
+            IF (L% MOD3)<>0 THEN ERROR42, "PNG palette must have R/G/B triplets"
+            L%=L% DIV3
+            FOR C%=0 TO L%-1
+              r%(C%)=BGET#c%/255*F
+              g%(C%)=BGET#c%/255*F
+              b%(C%)=BGET#c%/255*F
+            NEXT
+            C%=FNbeW:REM Skip CRC32
+          WHEN"IDAT"
+            IF (T% AND9)<>1 THEN V%=FALSE ELSE T%=T% OR4:REM Can be multiple, after IHDR, before IEND, PLTE optional
+            IF png1st%=0 AND L%<>0 THEN png1st%=PTR#c%-8:REM Latch first occupied IDAT for rewind
+            PTR#c%=PTR#c%+L%+4:REM Skip data & CRC32
+          WHEN"IEND"
+            IF (T% AND13)<>5 THEN V%=FALSE ELSE T%=T% OR8:REM Only once, must be last, PLTE optional
+            IF L%<>0 THEN ERROR42, "IEND contains data"
+            C%=FNbeW:REM Skip CRC32
+          OTHERWISE
+            PTR#c%=PTR#c%+L%+4:REM Skip unhandled tags
+        ENDCASE
+      UNTIL EOF#c%
+      IF NOT V% THEN ERROR42,"Out of order tag in PNG"
+      CASE PNGcol% OF
+        WHEN0:     IF PNGdep%<>1 AND PNGdep%<>2 AND PNGdep%<>4 AND PNGdep%<>8 AND PNGdep%<>16 THEN V%=FALSE
+        WHEN2,4,6: IF PNGdep%<>8 AND PNGdep%<>16 THEN V%=FALSE
+        WHEN3:     IF PNGdep%<>1 AND PNGdep%<>2 AND PNGdep%<>4 AND PNGdep%<>8 THEN V%=FALSE
+        OTHERWISE: V%=FALSE
+      ENDCASE
+      IF NOT V% THEN ERROR42,"Invalid PNG colour combination"
+      IF ((PNGcol%=0 OR PNGcol%=4) AND (T% AND2)=2) THEN ERROR42,"Unexpected palette with greyscale PNG"
+      IF (PNGcol%=3 AND (T% AND2)=0) THEN ERROR42,"Expected palette for colour indexed PNG"
+      IF PNGcmp%<>0 OR PNGflt%<>0 THEN ERROR42,"Unsupported compressor or filter type for PNG"
+      IF PNGint%<>0 AND PNGint%<>1 THEN ERROR42,"Unsupported interlacing scheme for PNG"
+      CASE PNGcol% OF
+        WHEN 0: quant%=PNGdep%:input=quant%+(8*(PNGdep%=16))
+                bppbytes%=(PNGdep%+7) DIV8:bppbits%=quant%
+                r$="FN4008":PROCflatpal(1<<input)
+        WHEN 2: quant%=3*PNGdep%:input=quant%
+                bppbytes%=3*(PNGdep% DIV8):bppbits%=quant%
+                r$="FN4024":PROCnopal:rbo%=0:gbo%=1*(PNGdep% DIV8):bbo%=2*(PNGdep% DIV8)
+        WHEN 3: quant%=PNGdep%:input=quant%
+                bppbytes%=1:bppbits%=quant%
+                r$="FN4008":REM Palette from PLTE tag
+        WHEN 4: quant%=PNGdep%:input=8
+                bppbytes%=2*(PNGdep% DIV8):bppbits%=2*PNGdep%
+                r$="FN4008":PROCflatpal(256)
+        WHEN 6: quant%=3*PNGdep%:input=quant%
+                bppbytes%=4*(PNGdep% DIV8):bppbits%=4*PNGdep%
+                r$="FN4024":PROCnopal:rbo%=0:gbo%=1*(PNGdep% DIV8):bbo%=2*(PNGdep% DIV8)
+      ENDCASE
+      IF PNGint%=1 THEN
+        s$="Interlaced"
+        pngsub%=7:DIM st%(7)
+        FOR S%=1 TO 7:REM For each subimage, calculate pixels per row
+          CASE S% OF
+            WHEN 1: st%(S%)=(sx%+7) DIV8
+            WHEN 2: st%(S%)=(sx%+3) DIV8
+            WHEN 3: st%(S%)=(sx%+3) DIV4:IF sy%<5 THEN st%(S%)=0:REM Empty
+            WHEN 4: st%(S%)=(sx%+1) DIV4
+            WHEN 5: st%(S%)=(sx%+1) DIV2:IF sy%<3 THEN st%(S%)=0:REM Empty
+            WHEN 6: st%(S%)=(sx%+0) DIV2
+            WHEN 7: st%(S%)=(sx%+0) DIV1:IF sy%<2 THEN st%(S%)=0:REM Empty
+          ENDCASE
+        NEXT
+      ELSE
+        s$="Progressive"
+        pngsub%=1:DIM st%(1)
+        st%(1)=sx%
+        pngbuff%=0
+      ENDIF
+      FOR S%=1 TO pngsub%:REM For each subimage, calculate whole bytes per row
+        CASE PNGcol% OF
+          WHEN 0,3:   st%(S%)=((st%(S%)*PNGdep%)+7) DIV8
+          WHEN 2,4,6: st%(S%)=st%(S%)*bppbytes%
+        ENDCASE
+      NEXT
+      PROCcachesize
+      datacache%=FNcachedim(cache%)
+      IF datacache%=-1 datacache%=FNdim(cache%)
+      pngspace%=cache% DIV pngsub%:REM Divide up the data cache equally by subimage
+      cache%=FALSE:REM Lines are compressed and interleaved with pesky IDATs, don't use built in refiller
+      buff%=FNdim(2*(SUM(st%())+pngsub%)):REM Current/previous rows, plus 1 extra for the filter type
+      IF PNGint%=1 THEN pngbuff%=FNdim(st%(7)+7):REM Extra row for deinterlacing, plus MAX(32,48,56) bit overshoot
+      A%=0:A%=USR (png%+0):pngblk%=FNdim(A%*pngsub%):REM Decompress state per subimage
+      PROCrewind
+      step24=bppbytes%
+      bigendianbits=TRUE
+      IF (PNGcol%=0 OR PNGcol%=4) THEN s$+=" greyscale" ELSE s$+=" colour"
+      info$=s$+" PNG, "+ STR$sx%+" by "+ STR$sy%+" pixels, "+FNbits(quant%)
   ENDCASE
   IF info% PRINT info$
   SYS "Hourglass_On"
@@ -10316,6 +10435,30 @@ DEF FN3724(z%())
 = TRUE
 :
 REM    
+DEF FN4008(z%())
+  A%=pngblk%
+  B%=c%
+  C%=pngy%:pngy%+=1
+  D%=sy%
+  E%=pngbuff%
+  rb%=USR (png%+4):REM Decompress a line of 8bpp-equivalent
+  CALL mappix%,z%(1,0),r%(0),g%(0),b%(0),rb%
+= TRUE
+:
+REM    
+DEF FN4024(z%())
+  A%=pngblk%
+  B%=c%
+  C%=pngy%:pngy%+=1
+  D%=sy%
+  E%=pngbuff%
+  rb%=USR (png%+4):REM Decompress a line of 24bpp-equivalent
+  gb%=rb%+gbo%
+  bb%=rb%+bbo%
+  CALL mappix%,z%(1,0),r%(0),g%(0),b%(0),rb%,gb%,bb%
+= TRUE
+:
+REM    
 DEF PROCrewind
   rows%=sy%
   CASE flag OF
@@ -10448,6 +10591,16 @@ DEF PROCrewind
       jpegy%=sy%
     WHEN 3900,3905
       PTR#c%=st%
+    WHEN 4000
+      pngy%=0
+      A%=pngblk%   
+      B%=buff%
+      C%=datacache%
+      D%=pngspace%
+      E%=png1st%
+      F%=bppbytes%+(bppbits%<<8)
+      G%=pngsub%
+      CALL (png%+0),st%(0):REM Prime the helper
   ENDCASE
   IF cache% THEN
     IF flag=3600 THEN