rockorager.dev
an experimental irc client
ui: draw scrollbar
+40
-9
src/Scrollbar.zig
+40
-9
src/Scrollbar.zig
···
1
const std = @import("std");
2
const vaxis = @import("vaxis");
3
4
const Scrollbar = @This();
5
···
10
style: vaxis.Style = .{},
11
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/// The index of the bottom-most item, with 0 being "at the bottom"
13
-
bottom: usize = 0,
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/// total items in the list
16
-
total: usize,
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/// total items that fit within the view area
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-
view_size: usize,
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21
-
pub fn draw(self: Scrollbar, win: vaxis.Window) void {
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// don't draw when 0 items
23
-
if (self.total < 1) return;
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// don't draw when all items can be shown
26
-
if (self.view_size >= self.total) return;
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// (view_size / total) * window height = size of the scroll bar
29
-
const bar_height = @max(std.math.divCeil(usize, self.view_size * win.height, self.total) catch unreachable, 1);
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// The row of the last cell of the bottom of the bar
32
-
const bar_bottom = (win.height - 1) -| (std.math.divCeil(usize, self.bottom * win.height, self.total) catch unreachable);
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var i: usize = 0;
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while (i <= bar_height) : (i += 1)
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-
win.writeCell(0, bar_bottom -| i, .{ .char = self.character, .style = self.style });
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}
···
1
const std = @import("std");
2
const vaxis = @import("vaxis");
3
+
const vxfw = vaxis.vxfw;
4
5
const Scrollbar = @This();
6
···
11
style: vaxis.Style = .{},
12
13
/// The index of the bottom-most item, with 0 being "at the bottom"
14
+
bottom: u16 = 0,
15
16
/// total items in the list
17
+
total: u16,
18
19
/// total items that fit within the view area
20
+
view_size: u16,
21
+
22
+
fn widget(self: *Scrollbar) vxfw.Widget {
23
+
return .{
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+
.userdata = self,
25
+
.drawFn = drawFn,
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+
};
27
+
}
28
+
29
+
fn drawFn(ptr: *anyopaque, ctx: vxfw.DrawContext) std.mem.Allocator.Error!vxfw.Surface {
30
+
const self: *Scrollbar = @ptrCast(@alignCast(ptr));
31
+
return self.draw(ctx);
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+
}
33
+
34
+
pub fn draw(self: *Scrollbar, ctx: vxfw.DrawContext) std.mem.Allocator.Error!vxfw.Surface {
35
+
const max = ctx.max.size();
36
+
if (max.width == 0 or max.height == 0) {
37
+
return .{
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+
.size = .{ .width = 0, .height = 0 },
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+
.widget = self.widget(),
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+
.buffer = &.{},
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+
.children = &.{},
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+
};
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+
}
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45
+
const surface = try vxfw.Surface.init(
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+
ctx.arena,
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+
self.widget(),
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+
.{ .width = 2, .height = max.height },
49
+
);
50
+
51
// don't draw when 0 items
52
+
if (self.total < 1) return surface;
53
54
// don't draw when all items can be shown
55
+
if (self.view_size >= self.total) return surface;
56
57
// (view_size / total) * window height = size of the scroll bar
58
+
const bar_height = @max(std.math.divCeil(usize, self.view_size * max.height, self.total) catch unreachable, 1);
59
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// The row of the last cell of the bottom of the bar
61
+
const bar_bottom = (max.height - 1) -| (std.math.divCeil(usize, self.bottom * max.height, self.total) catch unreachable);
62
63
var i: usize = 0;
64
while (i <= bar_height) : (i += 1)
65
+
surface.writeCell(0, @intCast(bar_bottom -| i), .{ .char = self.character, .style = self.style });
66
+
67
+
return surface;
68
}
+20
-1
src/irc.zig
+20
-1
src/irc.zig
···
6
const zeit = @import("zeit");
7
const bytepool = @import("pool.zig");
8
9
const testing = std.testing;
10
const mem = std.mem;
11
const vxfw = vaxis.vxfw;
···
463
464
const msg_view_ctx = ctx.withConstraints(.{ .height = 0, .width = 0 }, .{
465
.height = max.height - 4,
466
-
.width = max.width,
467
});
468
const message_view = try self.drawMessageView(msg_view_ctx);
469
try children.append(.{
470
.origin = .{ .row = 2, .col = 0 },
471
.surface = message_view,
472
});
473
474
// Draw the text field
···
6
const zeit = @import("zeit");
7
const bytepool = @import("pool.zig");
8
9
+
const Scrollbar = @import("Scrollbar.zig");
10
const testing = std.testing;
11
const mem = std.mem;
12
const vxfw = vaxis.vxfw;
···
464
465
const msg_view_ctx = ctx.withConstraints(.{ .height = 0, .width = 0 }, .{
466
.height = max.height - 4,
467
+
.width = max.width - 1,
468
});
469
const message_view = try self.drawMessageView(msg_view_ctx);
470
try children.append(.{
471
.origin = .{ .row = 2, .col = 0 },
472
.surface = message_view,
473
+
});
474
+
475
+
const scrollbar_ctx = ctx.withConstraints(
476
+
ctx.min,
477
+
.{ .width = 1, .height = max.height - 4 },
478
+
);
479
+
480
+
var scrollbars: Scrollbar = .{
481
+
// Estimate number of lines per message
482
+
.total = @intCast(self.messages.items.len * 3),
483
+
.view_size = max.height - 4,
484
+
.bottom = self.scroll.offset,
485
+
};
486
+
const scrollbar_surface = try scrollbars.draw(scrollbar_ctx);
487
+
// Draw the text field
488
+
try children.append(.{
489
+
.origin = .{ .col = max.width - 1, .row = 2 },
490
+
.surface = scrollbar_surface,
491
});
492
493
// Draw the text field