From cc20141b6dfc0f8721ead6a161374227c5bc61f7 Mon Sep 17 00:00:00 2001
From: Janis <janis@nirgendwo.xyz>
Date: Fri, 16 Dec 2022 17:04:03 +0100
Subject: [PATCH] image / surface spanning entire output

---
 main.zig | 118 ++++++++++++++++++++++++++++++++++++++++++++-----------
 1 file changed, 95 insertions(+), 23 deletions(-)

diff --git a/main.zig b/main.zig
index c0e68a7..475789c 100644
--- a/main.zig
+++ b/main.zig
@@ -48,6 +48,87 @@ const Selection = struct {
     }
 };
 
+const Buffer = struct {
+    const Self = @This();
+
+    buffer: *wl.Buffer = undefined,
+    cairo: struct {
+        surface: *cairo.cairo_surface_t = undefined,
+        ctx: *cairo.cairo_t = undefined,
+    } = .{},
+    size: Size = .{},
+    data: []u8 = undefined,
+
+    fn randomName() [13]u8 {
+        var name = [_]u8{'/', 'z', 'l', 'u','r','p','-','0','0','0','0','0','0'};
+
+        var rng = std.rand.DefaultPrng.init(@intCast(u64, std.time.milliTimestamp()));
+        for (name[7..]) |*c| {
+            c.* = rng.random().intRangeAtMost(u8, 'A', 'Z');
+        }
+
+        return name;
+    }
+
+    fn init(self: *Self, shm: *wl.Shm, size: Size) !void {
+        const name = randomName();
+        const stride = size.width * 4;
+        const len = stride * size.height;
+
+        const fd = try std.os.memfd_create(&name, 0);
+        defer std.os.close(fd);
+        try std.os.ftruncate(fd, len);
+
+        const data = try std.os.mmap(
+            null,
+            len,
+            std.os.PROT.READ | std.os.PROT.WRITE,
+            std.os.MAP.SHARED,
+            fd,
+            0,
+        );
+
+        const pool = try shm.createPool(fd, @intCast(i32, len));
+        defer pool.destroy();
+
+        const buffer = try pool.createBuffer(
+            0,
+            @intCast(i32, size.width),
+            @intCast(i32, size.height),
+            @intCast(i32, stride),
+            .argb8888,
+        );
+
+        const surface = cairo.cairo_image_surface_create_for_data(
+            @ptrCast([*c]u8, data),
+            cairo.CAIRO_FORMAT_ARGB32,
+            @intCast(c_int, size.width),
+            @intCast(c_int, size.height),
+            @intCast(c_int, stride),
+        ) orelse return error.NoCairoSurface;
+
+        const cairo_ctx = cairo.cairo_create(surface) orelse return error.NoCairoContext;
+
+        self.* = .{
+            .buffer = buffer,
+            .size = size,
+            .data = data,
+            .cairo = .{
+                .surface = surface,
+                .ctx = cairo_ctx,
+            },
+        };
+    }
+
+    fn deinit(self: *Self) void {
+        std.os.munmap(@alignCast(0x1000, self.data));
+        self.buffer.destroy();
+
+        cairo.cairo_destroy(self.cairo.ctx);
+        cairo.cairo_surface_destroy(self.cairo.surface);
+    }
+};
+
 const Box = struct {
     const Self = @This();
 
@@ -301,6 +382,10 @@ const Output = struct {
         self.output.destroy();
     }
 
+    fn commitFrame(self: *Self) void {
+        _ = self;
+    }
+
     fn xdgOutputListener(output: *zxdg.OutputV1, event: zxdg.OutputV1.Event, self: *Self) void {
         _ = output;
 
@@ -336,7 +421,7 @@ const Output = struct {
                 };
 
                 layer.ackConfigure(cfg.serial);
-                // TODO: send frame
+                self.commitFrame();
             },
             .closed => {
                 self.state.removeOutput(self);
@@ -832,32 +917,19 @@ const State = struct {
             var it = self.outputs.iterator(.forward);
             if (it.next()) |link| {
                 const output = link.get();
-                const os = std.os;
 
-                const buffer = blk: {
-                    const width = 128;
-                    const height = 128;
-                    const stride = width * 4;
-                    const size = stride * height;
+                var buffer: Buffer = undefined;
+                const width = output.size.width * @intCast(u32, output.scale);
+                const height = output.size.height * @intCast(u32, output.scale);
+                try buffer.init(self.shm, .{.width = width, .height = height});
+                std.mem.copy(u8, buffer.data, @embedFile("cat.bgra"));
 
-                    const fd = try os.memfd_create("hello-zig-wayland", 0);
-                    try os.ftruncate(fd, size);
-                    const data = try os.mmap(null, size, os.PROT.READ | os.PROT.WRITE, os.MAP.SHARED, fd, 0);
-                    std.mem.copy(u8, data, @embedFile("cat.bgra"));
-
-                    const pool = try self.shm.createPool(fd, size);
-                    defer pool.destroy();
-
-                    break :blk try pool.createBuffer(0, width, height, stride, wl.Shm.Format.argb8888);
-                };
-                defer buffer.destroy();
-
-                output.surface.attach(buffer, 0, 0);
+                output.surface.attach(buffer.buffer, 0, 0);
                 output.surface.commit();
+            }
 
-                while (self.running) {
-                    if (self.dpy.dispatch() != .SUCCESS) return error.DispatchFailed;
-                }
+            while (self.running) {
+                if (self.dpy.dispatch() != .SUCCESS) return error.DispatchFailed;
             }
         }