1 files changed, 100 insertions, 0 deletions
diff --git a/lib/Fornax/GenerateFrame.rakumod b/lib/Fornax/GenerateFrame.rakumod
new file mode 100644
index 0000000..e19d342
--- /dev/null
+++ b/lib/Fornax/GenerateFrame.rakumod
@@ -0,0 +1,100 @@
+use Cairo;
+use Fornax::Hex2RGB;
+
+# Cells as defined by fornax format.
+constant $PATH = '.';
+constant $BLOK = '#';
+constant $DEST = '$';
+constant $STRT = '^';
+constant $VIS = '-';
+constant $CUR = '@';
+constant $CURPATH = '~';
+
+# Colors.
+constant %C = (
+    bg-main => "#ffffff",
+
+    red-subtle-bg => "#f2b0a2",
+    blue-subtle-bg => "#b5d0ff",
+    cyan-subtle-bg => "#c0efff",
+    green-subtle-bg => "#aecf90",
+
+    fg-main => "#000000",
+
+    fg-special-cold => "#093060",
+    fg-special-warm => "#5d3026",
+    fg-special-mild => "#184034",
+    fg-special-calm => "#61284f",
+).map: {.key => hex2rgb(.value)};
+
+enum IterStatus <Walking Blocked Completed>;
+
+sub generate-frame(
+    :%CANVAS, :$out, :%excess, :$side, :%meta, :$iter is copy
+    , :$idx, :$debug,
+) is export {
+    my IterStatus $status;
+    given $iter.substr(0, 1) {
+        when '|' { $status = Completed }
+        when '!' { $status = Blocked }
+        default { $status = Walking }
+    };
+
+    # Remove marker.
+    $iter .= substr(1) if $status == Completed|Blocked;
+
+    put "\n[fornax] $idx $iter $status" if $debug;
+
+    my @grid = $iter.comb.rotor: %meta<cols>;
+    warn "Invalid grid: $idx $iter $status" unless @grid.elems == %meta<rows>;
+
+    given Cairo::Image.create(
+        Cairo::FORMAT_ARGB32, %CANVAS<width>, %CANVAS<height>
+    ) {
+        given Cairo::Context.new($_) {
+            # Paint the entire canvas white.
+            .rgb: |%C<bg-main>;
+            .rectangle(0, 0, %CANVAS<width>, %CANVAS<height>);
+            .fill;
+
+            # This seems to be slower than creating an intermediate
+            # variable and assigning from that. Difference is not much
+            # so we'll ignore it.
+            for ^%meta<rows> X ^%meta<cols>  -> ($r, $c) {
+                my Int @target = %excess<width> div 2 + $c * $side,
+                                 %excess<height> div 2 + $r * $side,
+                                 $side, $side;
+
+                .rectangle: |@target;
+
+                given @grid[$r][$c] -> $cell {
+                    # According to the format, current position may be
+                    # prioritized over Destination symbol so we
+                    # colorize it according to $status.
+                    when $cell eq $CUR {
+                        .rgba: |%C<fg-special-cold>, 0.56;
+                        .rgba: |%C<fg-special-mild>, 0.72 if $status == Completed;
+                        .rgba: |%C<fg-special-warm>, 0.72 if $status == Blocked;
+                    }
+                    when $cell eq $CURPATH {
+                        .rgba: |%C<blue-subtle-bg>, 0.84;
+                        .rgba: |%C<green-subtle-bg>, 0.96 if $status == Completed;
+                        .rgba: |%C<red-subtle-bg>, 0.96 if $status == Blocked;
+                    }
+                    when $cell eq $VIS {
+                        .rgba: |%C<cyan-subtle-bg>, 0.72;
+                    }
+                    when $cell eq $BLOK { .rgba: |%C<fg-main>, 0.56 }
+                    when $cell eq $STRT|$DEST { .rgba: |%C<fg-special-mild>, 0.72 }
+                    default { .rgba: |%C<fg-main>, 0.08 }
+                }
+                .fill :preserve;
+
+                .rgb: |%C<fg-main>;
+                .stroke;
+            }
+        }
+        .write_png($out);
+        .finish;
+    }
+}