Data commit

Task/Bitmap-Read-a-PPM-file/UNIX-Shell/bitmap-read-a-ppm-file-1.sh

@@ -0,0 +1,11 @@
+    function setrgb {
+        _.r=$1
+        _.g=$2
+        _.b=$3
+    }
+    function grayscale {
+        integer x=$(( round( 0.2126*_.r + 0.7152*_.g + 0.0722*_.b ) ))
+        _.r=$x
+        _.g=$x
+        _.b=$x
+    }

Task/Bitmap-Read-a-PPM-file/UNIX-Shell/bitmap-read-a-ppm-file-2.sh

@@ -0,0 +1,39 @@
+    function grayscale {
+        RGBColor_t c
+        for ((y=0; y<_.height; y++)); do
+            for ((x=0; x<_.width; x++)); do
+                c.setrgb ${_.data[y][x]}
+                c.grayscale
+                _.data[y][x]=$(c.to_s)
+            done
+        done
+    }
+
+    function read {
+        exec 4<"$1"
+        typeset filetype
+        read -u4 filetype
+        if [[ $filetype != "P3" ]]; then
+            print -u2 "error: I can only read P3 type PPM files"
+        else
+            read -u4 _.width _.height
+            integer maxval
+            read -u4 maxval
+            integer x y r g b
+            typeset -a bytes
+            for ((y=0; y<_.height; y++)); do
+                read -u4 -A bytes
+                for ((x=0; x<_.width; x++)); do
+                    r=${bytes[3*x+0]}
+                    g=${bytes[3*x+1]}
+                    b=${bytes[3*x+2]}
+                    if (( r > maxval || g > maxval || b > maxval )); then
+                        print -u2 "error: invalid color ($r $g $b), max=$maxval"
+                        return 1
+                    fi
+                    _.data[y][x]="$r $g $b"
+                done
+            done
+        fi
+        exec 4<&-
+    }

Task/Bitmap-Read-a-PPM-file/UNIX-Shell/bitmap-read-a-ppm-file-3.sh

@@ -0,0 +1,13 @@
+Bitmap_t c
+c.read "$HOME/tmp/bitmap.ppm"
+c.to_s
+
+if [[ $(c.to_s) == $(cat "$HOME/tmp/bitmap.ppm") ]]; then
+    echo looks OK
+else
+    echo something is wrong
+fi
+
+c.grayscale
+c.to_s
+c.write "$HOME/tmp/bitmap_g.ppm"