Add palette and odd-sized PNG unit tests. Fix loading interlaced PNGs < 8x8 in size.

basis/images/png/png-tests.factor

@@ -13,18 +13,62 @@ IN: images.png.tests
     "basi0g08.png" decode-test
     "basi0g16.png" decode-test
     "basi2c08.png" decode-test
+    "basi3p01.png" decode-test
+    "basi3p02.png" decode-test
+    "basi3p04.png" decode-test
+    "basi3p08.png" decode-test
     "basn0g01.png" decode-test
     "basn0g02.png" decode-test
     "basn0g04.png" decode-test
     "basn0g08.png" decode-test
     "basn0g16.png" decode-test
     "basn2c08.png" decode-test
+    "basn3p01.png" decode-test
+    "basn3p02.png" decode-test
+    "basn3p04.png" decode-test
+    "basn3p08.png" decode-test
     "basn6a08.png" decode-test
     "f00n2c08.png" decode-test
     "f01n2c08.png" decode-test
     "f02n2c08.png" decode-test
     "f03n2c08.png" decode-test
     "f04n2c08.png" decode-test
+    "s01i3p01.png" decode-test
+    "s01n3p01.png" decode-test
+    "s02i3p01.png" decode-test
+    "s02n3p01.png" decode-test
+    "s03i3p01.png" decode-test
+    "s03n3p01.png" decode-test
+    "s04i3p01.png" decode-test
+    "s04n3p01.png" decode-test
+    "s05i3p02.png" decode-test
+    "s05n3p02.png" decode-test
+    "s06i3p02.png" decode-test
+    "s06n3p02.png" decode-test
+    "s07i3p02.png" decode-test
+    "s07n3p02.png" decode-test
+    "s08i3p02.png" decode-test
+    "s08n3p02.png" decode-test
+    "s09i3p02.png" decode-test
+    "s32n3p04.png" decode-test
+    "s32i3p04.png" decode-test
+    "s33n3p04.png" decode-test
+    "s33i3p04.png" decode-test
+    "s34n3p04.png" decode-test
+    "s34i3p04.png" decode-test
+    "s35n3p04.png" decode-test
+    "s35i3p04.png" decode-test
+    "s36n3p04.png" decode-test
+    "s36i3p04.png" decode-test
+    "s37n3p04.png" decode-test
+    "s37i3p04.png" decode-test
+    "s38n3p04.png" decode-test
+    "s38i3p04.png" decode-test
+    "s39n3p04.png" decode-test
+    "s39i3p04.png" decode-test
+    "s40n3p04.png" decode-test
+    "s40i3p04.png" decode-test
+    "s07n3p02.png" decode-test
     "z00n2c08.png" decode-test
     "z03n2c08.png" decode-test
     "z06n2c08.png" decode-test

basis/images/png/png.factor

@@ -170,22 +170,35 @@ ERROR: bad-filter n ;
     byte-array bs:<msb0-bit-reader> :> bs
     loading-png width>> :> width
     loading-png height>> :> height
-
     bs loading-png width height read-scanlines ;
 
-: adam7-subimage-height ( png-height pass -- subimage-height )
-    [ starting-row nth + ] keep
-    row-increment nth /i ;
+:: adam7-subimage-height ( png-height pass -- subimage-height )
+    pass starting-row nth png-height >= [
+        0
+    ] [
+        png-height 1 -
+        pass block-height nth +
+        pass row-increment nth /i
+    ] if ;
 
-: adam7-subimage-width ( png-width pass -- subimage-width )
-    [ starting-col nth + ] keep
-    col-increment nth /i ;
+:: adam7-subimage-width ( png-width pass -- subimage-width )
+    pass starting-col nth png-width >= [
+        0
+    ] [
+        png-width 1 -
+        pass block-width nth +
+        pass col-increment nth /i
+    ] if ;
 
 :: read-adam7-subimage ( bit-reader loading-png pass -- lines )
     loading-png height>> pass adam7-subimage-height :> height
     loading-png width>> pass adam7-subimage-width :> width
 
-    bit-reader loading-png width height read-scanlines ;
+    height width * zero? [
+        B{ } clone
+    ] [
+        bit-reader loading-png width height read-scanlines
+    ] if ;
 
 :: reverse-interlace-adam7 ( byte-array loading-png -- byte-array )
     byte-array bs:<msb0-bit-reader> :> bs