ghostty/src/font/face.zig
2024-05-09 00:03:40 -04:00

112 lines
3.5 KiB
Zig

const std = @import("std");
const builtin = @import("builtin");
const options = @import("main.zig").options;
pub const Metrics = @import("face/Metrics.zig");
const freetype = @import("face/freetype.zig");
const coretext = @import("face/coretext.zig");
pub const web_canvas = @import("face/web_canvas.zig");
/// Face implementation for the compile options.
pub const Face = switch (options.backend) {
.freetype,
.fontconfig_freetype,
.coretext_freetype,
=> freetype.Face,
.coretext,
.coretext_harfbuzz,
.coretext_noshape,
=> coretext.Face,
.web_canvas => web_canvas.Face,
};
/// If a DPI can't be calculated, this DPI is used. This is probably
/// wrong on modern devices so it is highly recommended you get the DPI
/// using whatever platform method you can.
pub const default_dpi = if (builtin.os.tag == .macos) 72 else 96;
/// Options for initializing a font face.
pub const Options = struct {
size: DesiredSize,
metric_modifiers: ?*const Metrics.ModifierSet = null,
};
/// The desired size for loading a font.
pub const DesiredSize = struct {
// Desired size in points
points: f32,
// The DPI of the screen so we can convert points to pixels.
xdpi: u16 = default_dpi,
ydpi: u16 = default_dpi,
// Converts points to pixels
pub fn pixels(self: DesiredSize) u16 {
// 1 point = 1/72 inch
return @intFromFloat(@round((self.points * @as(f32, @floatFromInt(self.ydpi))) / 72));
}
};
/// A font variation setting. The best documentation for this I know of
/// is actually the CSS font-variation-settings property on MDN:
/// https://developer.mozilla.org/en-US/docs/Web/CSS/font-variation-settings
pub const Variation = struct {
id: Id,
value: f64,
pub const Id = packed struct(u32) {
d: u8,
c: u8,
b: u8,
a: u8,
pub fn init(v: *const [4]u8) Id {
return .{ .a = v[0], .b = v[1], .c = v[2], .d = v[3] };
}
/// Converts the ID to a string. The return value is only valid
/// for the lifetime of the self pointer.
pub fn str(self: Id) [4]u8 {
return .{ self.a, self.b, self.c, self.d };
}
};
};
/// Additional options for rendering glyphs.
pub const RenderOptions = struct {
/// The metrics that are defining the grid layout. These are usually
/// the metrics of the primary font face. The grid metrics are used
/// by the font face to better layout the glyph in situations where
/// the font is not exactly the same size as the grid.
grid_metrics: ?Metrics = null,
/// The number of grid cells this glyph will take up. This can be used
/// optionally by the rasterizer to better layout the glyph.
cell_width: ?u2 = null,
/// Thicken the glyph. This draws the glyph with a thicker stroke width.
/// This is purely an aesthetic setting.
///
/// This only works with CoreText currently.
thicken: bool = false,
};
test {
@import("std").testing.refAllDecls(@This());
}
test "Variation.Id: wght should be 2003265652" {
const testing = std.testing;
const id = Variation.Id.init("wght");
try testing.expectEqual(@as(u32, 2003265652), @as(u32, @bitCast(id)));
try testing.expectEqualStrings("wght", &(id.str()));
}
test "Variation.Id: slnt should be 1936486004" {
const testing = std.testing;
const id: Variation.Id = .{ .a = 's', .b = 'l', .c = 'n', .d = 't' };
try testing.expectEqual(@as(u32, 1936486004), @as(u32, @bitCast(id)));
try testing.expectEqualStrings("slnt", &(id.str()));
}