Add ASCII Background Animation

res/config.ini

@@ -24,6 +24,7 @@ allow_empty_password = true
 # matrix   -> CMatrix
 # colormix -> Color mixing shader
 # gameoflife -> John Conway's Game of Life
+# ascii    -> Custom ASCII art background loaded from a file
 animation = none
 
 # Stop the animation after some time
@@ -155,6 +156,17 @@ gameoflife_frame_delay = 6
 # 0.7+ -> Dense, chaotic patterns
 gameoflife_initial_density = 0.4
 
+# ASCII background file path (absolute)
+ascii_filename = /etc/ly/config.ini
+
+# ASCII background text foreground color id
+ascii_fg = 0x00FFFFFF
+
+# ASCII background offset (top left = 0,0; specified in characters)
+# These must be >= 0
+ascii_x = 0
+ascii_y = 0
+
 # Remove main box borders
 hide_borders = false
 

src/animations/Ascii.zig

@@ -0,0 +1,91 @@
+const std = @import("std");
+const Animation = @import("../tui/Animation.zig");
+const Cell = @import("../tui/Cell.zig");
+const TerminalBuffer = @import("../tui/TerminalBuffer.zig");
+
+const Ascii = @This();
+
+const MAX_WIDTH  = 512;
+const MAX_HEIGHT = 256;
+
+terminal_buffer: *TerminalBuffer,
+ascii_art: [MAX_HEIGHT][MAX_WIDTH]u8 = undefined,
+line_len: [MAX_HEIGHT]usize = undefined,
+line_count: usize = undefined,
+fg: u32 = undefined,
+x: u32 = undefined,
+y: u32 = undefined,
+
+pub fn init(terminal_buffer: *TerminalBuffer, filename: []const u8, fg: u32, x: u32, y: u32) !Ascii {
+    var ascii_art: [MAX_HEIGHT][MAX_WIDTH]u8 = undefined;
+    var line_len: [MAX_HEIGHT]usize = [_]usize{0} ** MAX_HEIGHT;
+    var line_count: usize = 0;
+
+    var file = std.fs.openFileAbsolute(filename, .{}) catch {
+        std.log.err("ASCII background file not found: {s}", .{filename});
+        return .{
+            .terminal_buffer = terminal_buffer,
+            .ascii_art = undefined, // Undefined buffers here are safe, as line_count
+            .line_len = undefined,  // is set to 0 so nothing will be drawn
+            .line_count = 0,
+            .fg = 0x00000000,
+            .x = 0, .y = 0,
+        };
+    };
+    var reader = file.reader();
+    defer file.close();
+
+    while (line_count < MAX_HEIGHT) {
+        const line = reader.readUntilDelimiterOrEof(&ascii_art[line_count], '\n') catch |err| switch (err) {
+            error.StreamTooLong => {
+                _ = try reader.skipUntilDelimiterOrEof('\n'); // consume remainder of line
+                line_len[line_count] = MAX_WIDTH;
+                line_count += 1;
+                continue;
+            },
+            else => return err,
+        } orelse break;
+
+        line_len[line_count] = line.len;
+        line_count += 1;
+    }
+
+    return .{
+        .terminal_buffer = terminal_buffer,
+        .ascii_art = ascii_art,
+        .line_len = line_len,
+        .line_count = line_count,
+        .fg = fg, .x = x, .y = y,
+    };
+}
+pub fn animation(self: *Ascii) Animation {
+    return Animation.init(self, deinit, realloc, draw);
+}
+
+fn deinit(_: *Ascii) void {}
+
+fn realloc(_: *Ascii) anyerror!void {}
+
+fn min(a: usize, b: usize) usize {
+    if (a < b) return a;
+    return b;
+}
+
+fn draw(self: *Ascii) void {
+    const buf_width = self.terminal_buffer.width;
+    const buf_height = self.terminal_buffer.height;
+
+    var y: usize = 0;
+    while (y < min(buf_height, self.line_count)) : (y += 1) {
+        const line_width = self.line_len[y];
+        var x: usize = 0;
+        while (x < min(buf_width, line_width)) : (x += 1) {
+            const cell = Cell {
+                .ch = self.ascii_art[y][x],
+                .fg = self.fg,
+                .bg = self.terminal_buffer.bg,
+            };
+            cell.put(x + self.x, y + self.y);
+        }
+    }
+}

src/config/Config.zig

@@ -42,6 +42,10 @@ gameoflife_fg: u32 = 0x0000FF00,
 gameoflife_entropy_interval: usize = 10,
 gameoflife_frame_delay: usize = 6,
 gameoflife_initial_density: f32 = 0.4,
+ascii_filename: []const u8 = "/etc/ly/config.ini",
+ascii_fg: u32 = 0x00FF0000,
+ascii_x: u32 = 0,
+ascii_y: u32 = 0,
 hide_borders: bool = false,
 hide_version_string: bool = false,
 hide_key_hints: bool = false,

src/enums.zig

@@ -4,6 +4,7 @@ pub const Animation = enum {
     matrix,
     colormix,
     gameoflife,
+    ascii,
 };
 
 pub const DisplayServer = enum {

src/main.zig

@@ -13,6 +13,7 @@ const Doom = @import("animations/Doom.zig");
 const Dummy = @import("animations/Dummy.zig");
 const Matrix = @import("animations/Matrix.zig");
 const GameOfLife = @import("animations/GameOfLife.zig");
+const Ascii = @import("animations/Ascii.zig");
 const Animation = @import("tui/Animation.zig");
 const TerminalBuffer = @import("tui/TerminalBuffer.zig");
 const Session = @import("tui/components/Session.zig");
@@ -400,6 +401,10 @@ pub fn main() !void {
             var game_of_life = try GameOfLife.init(allocator, &buffer, config.gameoflife_fg, config.gameoflife_entropy_interval, config.gameoflife_frame_delay, config.gameoflife_initial_density);
             animation = game_of_life.animation();
         },
+        .ascii => {
+            var ascii = try Ascii.init(&buffer, config.ascii_filename, config.ascii_fg, config.ascii_x, config.ascii_y);
+            animation = ascii.animation();
+        },
     }
     defer animation.deinit();