1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
#![windows_subsystem = "windows"]
use pulldown_cmark::{Event as ParseEvent, Parser, Tag};
use druid::text::{AttributesAdder, RichText, RichTextBuilder};
use druid::widget::prelude::*;
use druid::widget::{Controller, LineBreaking, RawLabel, Scroll, Split, TextBox};
use druid::{
AppDelegate, AppLauncher, Color, Command, Data, DelegateCtx, FontFamily, FontStyle, FontWeight,
Handled, Lens, LocalizedString, Menu, Selector, Target, Widget, WidgetExt, WindowDesc,
WindowId,
};
const WINDOW_TITLE: LocalizedString<AppState> = LocalizedString::new("Minimal Markdown");
const TEXT: &str = "*Hello* ***world***! This is a `TextBox` where you can \
use limited markdown notation, which is reflected in the \
**styling** of the `Label` on the left.
If you're curious about Druid, a good place to ask questions \
and discuss development work is our [Zulip chat instance], \
in the #druid-help and #druid channels, respectively.\n\n\n\
[Zulip chat instance]: https://xi.zulipchat.com";
const SPACER_SIZE: f64 = 8.0;
const BLOCKQUOTE_COLOR: Color = Color::grey8(0x88);
const LINK_COLOR: Color = Color::rgb8(0, 0, 0xEE);
const OPEN_LINK: Selector<String> = Selector::new("druid-example.open-link");
#[derive(Clone, Data, Lens)]
struct AppState {
raw: String,
rendered: RichText,
}
struct RichTextRebuilder;
impl<W: Widget<AppState>> Controller<AppState, W> for RichTextRebuilder {
fn event(
&mut self,
child: &mut W,
ctx: &mut EventCtx,
event: &Event,
data: &mut AppState,
env: &Env,
) {
let pre_data = data.raw.to_owned();
child.event(ctx, event, data, env);
if !data.raw.same(&pre_data) {
data.rendered = rebuild_rendered_text(&data.raw);
}
}
}
struct Delegate;
impl<T: Data> AppDelegate<T> for Delegate {
fn command(
&mut self,
_ctx: &mut DelegateCtx,
_target: Target,
cmd: &Command,
_data: &mut T,
_env: &Env,
) -> Handled {
if let Some(url) = cmd.get(OPEN_LINK) {
#[cfg(not(target_arch = "wasm32"))]
open::that_in_background(url);
#[cfg(target_arch = "wasm32")]
tracing::warn!("opening link({}) not supported on web yet.", url);
Handled::Yes
} else {
Handled::No
}
}
}
pub fn main() {
let main_window = WindowDesc::new(build_root_widget())
.title(WINDOW_TITLE)
.menu(make_menu)
.window_size((700.0, 600.0));
let initial_state = AppState {
raw: TEXT.to_owned(),
rendered: rebuild_rendered_text(TEXT),
};
AppLauncher::with_window(main_window)
.log_to_console()
.delegate(Delegate)
.launch(initial_state)
.expect("Failed to launch application");
}
fn build_root_widget() -> impl Widget<AppState> {
let label = Scroll::new(
RawLabel::new()
.with_text_color(Color::BLACK)
.with_line_break_mode(LineBreaking::WordWrap)
.lens(AppState::rendered)
.expand_width()
.padding((SPACER_SIZE * 4.0, SPACER_SIZE)),
)
.vertical()
.background(Color::grey8(222))
.expand();
let textbox = TextBox::multiline()
.lens(AppState::raw)
.controller(RichTextRebuilder)
.expand()
.padding(5.0);
Split::columns(label, textbox)
}
fn rebuild_rendered_text(text: &str) -> RichText {
let mut current_pos = 0;
let mut builder = RichTextBuilder::new();
let mut tag_stack = Vec::new();
let parser = Parser::new(text);
for event in parser {
match event {
ParseEvent::Start(tag) => {
tag_stack.push((current_pos, tag));
}
ParseEvent::Text(txt) => {
builder.push(&txt);
current_pos += txt.len();
}
ParseEvent::End(end_tag) => {
let (start_off, tag) = tag_stack
.pop()
.expect("parser does not return unbalanced tags");
assert_eq!(end_tag, tag, "mismatched tags?");
add_attribute_for_tag(
&tag,
builder.add_attributes_for_range(start_off..current_pos),
);
if add_newline_after_tag(&tag) {
builder.push("\n\n");
current_pos += 2;
}
}
ParseEvent::Code(txt) => {
builder.push(&txt).font_family(FontFamily::MONOSPACE);
current_pos += txt.len();
}
ParseEvent::Html(txt) => {
builder
.push(&txt)
.font_family(FontFamily::MONOSPACE)
.text_color(BLOCKQUOTE_COLOR);
current_pos += txt.len();
}
ParseEvent::HardBreak => {
builder.push("\n\n");
current_pos += 2;
}
_ => (),
}
}
builder.build()
}
fn add_newline_after_tag(tag: &Tag) -> bool {
!matches!(
tag,
Tag::Emphasis | Tag::Strong | Tag::Strikethrough | Tag::Link(..)
)
}
fn add_attribute_for_tag(tag: &Tag, mut attrs: AttributesAdder) {
match tag {
Tag::Heading(lvl) => {
let font_size = match lvl {
1 => 38.,
2 => 32.0,
3 => 26.0,
4 => 20.0,
5 => 16.0,
_ => 12.0,
};
attrs.size(font_size).weight(FontWeight::BOLD);
}
Tag::BlockQuote => {
attrs.style(FontStyle::Italic).text_color(BLOCKQUOTE_COLOR);
}
Tag::CodeBlock(_) => {
attrs.font_family(FontFamily::MONOSPACE);
}
Tag::Emphasis => {
attrs.style(FontStyle::Italic);
}
Tag::Strong => {
attrs.weight(FontWeight::BOLD);
}
Tag::Link(_link_ty, target, _title) => {
attrs
.underline(true)
.text_color(LINK_COLOR)
.link(OPEN_LINK.with(target.to_string()));
}
_ => (),
}
}
#[allow(unused_assignments, unused_mut)]
fn make_menu<T: Data>(_window_id: Option<WindowId>, _app_state: &AppState, _env: &Env) -> Menu<T> {
let mut base = Menu::empty();
#[cfg(target_os = "macos")]
{
base = base.entry(druid::platform_menus::mac::application::default())
}
#[cfg(any(target_os = "windows", target_os = "linux"))]
{
base = base.entry(druid::platform_menus::win::file::default());
}
base.entry(
Menu::new(LocalizedString::new("common-menu-edit-menu"))
.entry(druid::platform_menus::common::undo())
.entry(druid::platform_menus::common::redo())
.separator()
.entry(druid::platform_menus::common::cut().enabled(false))
.entry(druid::platform_menus::common::copy())
.entry(druid::platform_menus::common::paste()),
)
}