images: move to subfolder, use union enum for implementations

There will only ever be a handful of image implementations. Let's just
use a union enum for handling them.

Signed-off-by: Tim Culverhouse <tim@timculverhouse.com>

src/Image.zig

@@ -1,84 +0,0 @@
-const std = @import("std");
-const math = std.math;
-const testing = std.testing;
-const zigimg = @import("zigimg");
-
-const Window = @import("Window.zig");
-const Winsize = @import("Tty.zig").Winsize;
-
-const Image = @This();
-
-pub const Source = union(enum) {
-    /// loads an image from a path. path can be relative to cwd, or absolute
-    path: []const u8,
-    /// loads an image from raw bytes
-    mem: []const u8,
-};
-
-pub const Protocol = enum {
-    kitty,
-    // TODO: sixel, full block, half block, quad block
-};
-
-/// the decoded image
-img: zigimg.Image,
-
-/// unique identifier for this image
-id: u32,
-
-/// width of the image, in cells
-cell_width: usize,
-/// height of the image, in cells
-cell_height: usize,
-
-/// initialize a new image
-pub fn init(
-    alloc: std.mem.Allocator,
-    winsize: Winsize,
-    src: Source,
-    id: u32,
-) !Image {
-    const img = switch (src) {
-        .path => |path| try zigimg.Image.fromFilePath(alloc, path),
-        .mem => |bytes| try zigimg.Image.fromMemory(alloc, bytes),
-    };
-    // cell geometry
-    const pix_per_col = try math.divCeil(usize, winsize.x_pixel, winsize.cols);
-    const pix_per_row = try math.divCeil(usize, winsize.y_pixel, winsize.rows);
-
-    const cell_width = math.divCeil(usize, img.width, pix_per_col) catch 0;
-    const cell_height = math.divCeil(usize, img.height, pix_per_row) catch 0;
-
-    return Image{
-        .img = img,
-        .cell_width = cell_width,
-        .cell_height = cell_height,
-        .id = id,
-    };
-}
-
-pub fn deinit(self: *Image) void {
-    self.img.deinit();
-}
-
-pub fn draw(self: *Image, win: Window, placement_id: u32) !void {
-    try win.writeImage(win.x_off, win.y_off, self, placement_id);
-}
-
-test "image" {
-    const alloc = testing.allocator;
-    var img = try init(
-        alloc,
-        .{
-            .rows = 1,
-            .cols = 1,
-            .x_pixel = 1,
-            .y_pixel = 1,
-        },
-        .{ .path = "vaxis.png" },
-        1,
-    );
-    defer img.deinit();
-    try testing.expectEqual(200, img.cell_width);
-    try testing.expectEqual(197, img.cell_height);
-}

src/InternalScreen.zig

@@ -3,7 +3,7 @@ const assert = std.debug.assert;
 const Style = @import("cell.zig").Style;
 const Cell = @import("cell.zig").Cell;
 const Shape = @import("Mouse.zig").Shape;
-const Image = @import("Image.zig").Placement;
+const Image = @import("image/image.zig").Image;
 const Placement = @import("Screen.zig").Placement;
 
 const log = std.log.scoped(.internal_screen);

src/Screen.zig

@@ -3,7 +3,7 @@ const assert = std.debug.assert;
 
 const Cell = @import("cell.zig").Cell;
 const Shape = @import("Mouse.zig").Shape;
-const Image = @import("Image.zig");
+const Image = @import("image/image.zig").Image;
 
 const log = std.log.scoped(.screen);
 
@@ -14,6 +14,14 @@ pub const Placement = struct {
     placement_id: u32,
     col: usize,
     row: usize,
+
+    /// two placements are considered equal if their image id and their
+    /// placement id are equal
+    pub fn eql(self: Placement, tgt: Placement) bool {
+        if (self.img.getId() != tgt.img.getId()) return false;
+        if (self.placement_id != tgt.placement_id) return false;
+        return true;
+    }
 };
 
 width: usize = 0,

src/Window.zig

@@ -2,7 +2,7 @@ const std = @import("std");
 
 const Screen = @import("Screen.zig");
 const Cell = @import("cell.zig").Cell;
-const Image = @import("Image.zig");
+const Image = @import("image/image.zig").Image;
 const gw = @import("gwidth.zig");
 
 const log = std.log.scoped(.window);
@@ -69,17 +69,14 @@ pub fn writeCell(self: Window, col: usize, row: usize, cell: Cell) void {
     self.screen.writeCell(col + self.x_off, row + self.y_off, cell);
 }
 
-/// writes a cell to the location in the window
+/// writes an image to the location in the window
 pub fn writeImage(
     self: Window,
-    col: usize,
-    row: usize,
     img: *Image,
     placement_id: u32,
 ) !void {
     if (self.height == 0 or self.width == 0) return;
-    if (self.height <= row or self.width <= col) return;
+    self.screen.writeImage(self.x_off, self.y_off, img, placement_id);
-    self.screen.writeImage(col, row, img, placement_id);
 }
 
 /// fills the window with the default cell

src/image/Kitty.zig

@@ -12,63 +12,25 @@ const Kitty = @This();
 /// the decoded image
 img: zigimg.Image,
 
-/// unique identifier for this image
+/// unique identifier for this image. This will be managed by the screen. The ID
-id: u32,
+/// is only null for images which have not been transmitted to the screen
+id: ?u32 = null,
 
 /// width of the image, in cells
 cell_width: usize,
 /// height of the image, in cells
 cell_height: usize,
 
-/// initialize a new image
+pub fn deinit(self: *Kitty) void {
-pub fn init(
-    alloc: std.mem.Allocator,
-    winsize: Winsize,
-    src: []const u8,
-    id: u32,
-) !Kitty {
-    const img = switch (src) {
-        .path => |path| try zigimg.Image.fromFilePath(alloc, path),
-        .mem => |bytes| try zigimg.Image.fromMemory(alloc, bytes),
-    };
-    // cell geometry
-    const pix_per_col = try math.divCeil(usize, winsize.x_pixel, winsize.cols);
-    const pix_per_row = try math.divCeil(usize, winsize.y_pixel, winsize.rows);
-
-    const cell_width = math.divCeil(usize, img.width, pix_per_col) catch 0;
-    const cell_height = math.divCeil(usize, img.height, pix_per_row) catch 0;
-
-    return Image{
-        .img = img,
-        .cell_width = cell_width,
-        .cell_height = cell_height,
-        .id = id,
-    };
-}
-
-pub fn deinit(self: *Image) void {
     self.img.deinit();
 }
 
-pub fn draw(self: *Image, win: Window, placement_id: u32) !void {
+pub fn draw(self: *Kitty, win: Window) !void {
-    try win.writeImage(win.x_off, win.y_off, self, placement_id);
+    const row: u16 = @truncate(win.y_off);
-}
+    const col: u16 = @truncate(win.x_off);
-
+    // the placement id has the high 16 bits as the column and the low 16
-test "image" {
+    // bits as the row. This means we can only place this image one time at
-    const alloc = testing.allocator;
+    // the same location - which is completely sane
-    var img = try init(
+    const pid: u32 = col << 16 | row;
-        alloc,
+    try win.writeImage(win.x_off, win.y_off, self, pid);
-        .{
-            .rows = 1,
-            .cols = 1,
-            .x_pixel = 1,
-            .y_pixel = 1,
-        },
-        .{ .path = "vaxis.png" },
-        0,
-        .kitty,
-    );
-    defer img.deinit();
-    try testing.expectEqual(200, img.cell_width);
-    try testing.expectEqual(197, img.cell_height);
 }

src/image/image.zig

@@ -8,35 +8,60 @@ const Window = @import("../Window.zig");
 
 const Kitty = @import("Kitty.zig");
 
+pub const Protocol = enum {
+    kitty,
+    // TODO: sixel, full block, half block, quad block
+};
+
 pub const Image = union(enum) {
     kitty: Kitty,
 
-    pub const Protocol = enum {
-        kitty,
-        // TODO: sixel, full block, half block, quad block
-    };
-
     /// initialize a new image
     pub fn init(
         alloc: std.mem.Allocator,
         winsize: Winsize,
         src: []const u8,
-        id: u32,
         protocol: Protocol,
     ) !Image {
+        const img = switch (src) {
+            .path => |path| try zigimg.Image.fromFilePath(alloc, path),
+            .mem => |bytes| try zigimg.Image.fromMemory(alloc, bytes),
+        };
+        // cell geometry
+        const pix_per_col = try math.divCeil(usize, winsize.x_pixel, winsize.cols);
+        const pix_per_row = try math.divCeil(usize, winsize.y_pixel, winsize.rows);
+
+        const cell_width = math.divCeil(usize, img.width, pix_per_col) catch 0;
+        const cell_height = math.divCeil(usize, img.height, pix_per_row) catch 0;
+
         switch (protocol) {
             .kitty => {
-                const img = try Kitty.init(alloc, winsize, src, id);
+                return .{
-                return .{ .kitty = img };
+                    .kitty = Kitty{
+                        .img = img,
+                        .cell_width = cell_width,
+                        .cell_height = cell_height,
+                    },
+                };
             },
         }
     }
 
-    pub fn deinit(self: *Image) void {
+    pub fn deinit(self: Image) void {
-        self.img.deinit();
+        switch (self) {
+            inline else => |case| case.deinit(),
+        }
     }
 
-    pub fn draw(self: *Image, win: Window, placement_id: u32) !void {
+    pub fn draw(self: Image, win: Window) !void {
-        try win.writeImage(win.x_off, win.y_off, self, placement_id);
+        switch (self) {
+            inline else => |case| case.draw(win),
+        }
+    }
+
+    pub fn getId(self: Image) ?u32 {
+        switch (self) {
+            .kitty => |k| return k.id,
+        }
     }
 };

src/main.zig

@@ -17,7 +17,6 @@ pub fn init(comptime EventType: type, opts: Options) !Vaxis(EventType) {
 
 test {
     _ = @import("GraphemeCache.zig");
-    _ = @import("Image.zig");
     _ = @import("Key.zig");
     _ = @import("Mouse.zig");
     _ = @import("Options.zig");
@@ -29,6 +28,7 @@ test {
     _ = @import("ctlseqs.zig");
     _ = @import("event.zig");
     _ = @import("gwidth.zig");
+    _ = @import("image/image.zig");
     _ = @import("queue.zig");
     _ = @import("vaxis.zig");
 }

src/vaxis.zig

@@ -280,13 +280,24 @@ pub fn Vaxis(comptime T: type) type {
             var cursor: Style = .{};
             var link: Hyperlink = .{};
 
-            // delete remove images from the screen by looping through the
+            // remove images from the screen by looping through the last state
-            // current state and comparing to the next state
+            // and comparing to the next state
             for (self.screen_last.images.items) |last_img| {
                 const keep: bool = for (self.screen.images.items) |next_img| {
-                    if (std.meta.eql(last_img, next_img)) break true;
+                    if (last_img.eql(next_img)) break true;
                 } else false;
                 if (keep) continue;
+                // TODO: remove image placements
+            }
+
+            // add new images. Could slightly optimize by knowing which images
+            // we need to keep from the remove loop
+            for (self.screen.images.items) |img| {
+                const transmit: bool = for (self.screen_last.images.items) |last_img| {
+                    if (last_img.eql(img)) break false;
+                } else true;
+                if (!transmit) continue;
+                // TODO: transmit the new image to the screen
             }
 
             var i: usize = 0;