tons of updates, added examples

imgui-examples/examples/keyboard.rs

@@ -11,8 +11,7 @@ fn main() {
     let mut uncaptured_counter = 0u32;
     let mut home_counter = 0u32;
     let mut f1_release_count = 0u32;
-    let mut text_buffer = ImString::new("with some buffer");
-    text_buffer.reserve(100);
+    let mut text_buffer = ImString::new("");
 
     system.main_loop(move |_, ui| {
         Window::new(im_str!("Means of accessing key state"))

imgui-examples/examples/text_callbacks.rs

@@ -0,0 +1,151 @@
+use imgui::*;
+
+mod support;
+
+fn main() {
+    let system = support::init(file!());
+    let mut buffers = vec![
+        ImString::default(),
+        ImString::default(),
+        ImString::default(),
+    ];
+
+    system.main_loop(move |_, ui| {
+        Window::new(im_str!("Input text callbacks"))
+            .size([500.0, 300.0], Condition::FirstUseEver)
+            .build(ui, || {
+                ui.text("You can make a variety of buffer callbacks on an Input Text");
+                ui.text(
+                    "or on an InputTextMultiline. In this example, we'll use \
+                InputText primarily.",
+                );
+                ui.text(
+                    "The only difference is that InputTextMultiline doesn't get \
+                the `History` callback,",
+                );
+                ui.text("since, of course, you need the up/down keys to navigate.");
+
+                ui.separator();
+
+                ui.text("No callbacks:");
+                ui.input_text(im_str!("buf0"), &mut buffers[0]).build();
+                ui.input_text(im_str!("buf0"), &mut buffers[1]).build();
+                ui.input_text(im_str!("buf0"), &mut buffers[2]).build();
+
+                ui.separator();
+
+                ui.text("Here's a callback which printlns when each is ran.");
+
+                struct AllCallback;
+                impl InputTextCallbackHandler for AllCallback {
+                    fn char_filter(&mut self, c: char) -> Option<char> {
+                        println!("Char filter fired! This means a char was inputted.");
+                        Some(c)
+                    }
+                    fn on_completion(&mut self, _: TextCallbackData<'_>) {
+                        println!("Completion request fired! This means the tab key was hit.");
+                    }
+
+                    fn on_edit(&mut self, _: TextCallbackData<'_>) {
+                        println!("Edit was fired! Any edit will cause this to fire.")
+                    }
+
+                    fn on_history(&mut self, dir: HistoryDirection, _: TextCallbackData<'_>) {
+                        println!("History was fired by pressing {:?}", dir);
+                    }
+
+                    fn on_always(&mut self, _: TextCallbackData<'_>) {
+                        // We don't actually print this out because it will flood your log a lot!
+                        // println!("The always callback fired! It always fires.");
+                    }
+                }
+
+                ui.input_text(
+                    im_str!("All Callbacks logging"),
+                    buffers.get_mut(0).unwrap(),
+                )
+                .callback(InputTextCallback::all(), AllCallback)
+                .build();
+
+                ui.separator();
+
+                ui.text("You can also define a callback on structs with data.");
+                ui.text("Here we implement the callback handler on a wrapper around &mut ImString");
+                ui.text("to duplicate edits to buf0 on buf1");
+
+                struct Wrapper<'a>(&'a mut ImString);
+                impl<'a> InputTextCallbackHandler for Wrapper<'a> {
+                    fn on_always(&mut self, data: TextCallbackData<'_>) {
+                        *self.0 = im_str!("{}", data.str());
+                    }
+                }
+
+                let (buf0, brwchk_dance) = buffers.split_first_mut().unwrap();
+                let buf1 = Wrapper(&mut brwchk_dance[0]);
+
+                ui.input_text(im_str!("Edits copied to buf1"), buf0)
+                    .callback(InputTextCallback::ALWAYS, buf1)
+                    .build();
+
+                ui.separator();
+
+                ui.text("Finally, we'll do some whacky history to show inserting and removing");
+                ui.text("characters from the buffer.");
+                ui.text(
+                    "Here, pressing UP (while editing the below widget) will remove the\n\
+                first and last character from buf2",
+                );
+                ui.text("and pressing DOWN will prepend the first char from buf0 AND");
+                ui.text("append the last char from buf1");
+
+                let (buf0, brwchk_dance) = buffers.split_first_mut().unwrap();
+                let (buf1, buf2_dance) = brwchk_dance.split_first_mut().unwrap();
+                let buf2 = &mut buf2_dance[0];
+
+                struct Wrapper2<'a>(&'a str, &'a str);
+
+                impl<'a> InputTextCallbackHandler for Wrapper2<'a> {
+                    fn on_history(
+                        &mut self,
+                        dir: HistoryDirection,
+                        mut data: TextCallbackData<'_>,
+                    ) {
+                        match dir {
+                            HistoryDirection::Up => {
+                                // remove first char...
+                                if !data.str().is_empty() {
+                                    data.remove_chars(0, 1);
+
+                                    if let Some((idx, _)) = data.str().char_indices().rev().next() {
+                                        data.remove_chars(idx, 1);
+                                    }
+                                }
+                            }
+                            HistoryDirection::Down => {
+                                // insert first char...
+                                if let Some(first_char) = self.0.get(0..1) {
+                                    data.insert_chars(0, first_char);
+                                }
+
+                                // insert last char
+                                if let Some((idx, _)) = self.1.char_indices().rev().next() {
+                                    data.push_str(&self.1[idx..]);
+                                }
+                            }
+                        }
+                    }
+                }
+
+                ui.input_text(im_str!("Wild buf2 editor"), buf2)
+                    .callback(
+                        InputTextCallback::HISTORY,
+                        Wrapper2(buf0.to_str(), buf1.to_str()),
+                    )
+                    .build();
+
+                ui.text(
+                    "For more examples on how to use callbacks non-chaotically, check the demo",
+                );
+            });
+    });
+}

imgui/src/input_widget.rs

@@ -183,7 +183,7 @@ impl<'ui, 'p> InputText<'ui, 'p, PassthroughCallback> {
     }
 }
 
-impl<'ui, 'p, T: TextCallbackHandler> InputText<'ui, 'p, T> {
+impl<'ui, 'p, T: InputTextCallbackHandler> InputText<'ui, 'p, T> {
     /// Sets the hint displayed in the input text background.
     #[inline]
     pub fn hint(mut self, hint: &'p ImStr) -> Self {
@@ -194,7 +194,7 @@ impl<'ui, 'p, T: TextCallbackHandler> InputText<'ui, 'p, T> {
     impl_text_flags!(InputText);
 
     /// By default (as of 0.8.0), imgui-rs will automatically handle string resizes
-    /// for `InputText` and `InputTextMultiline`.
+    /// for [InputText] and [InputTextMultiline].
     ///
     /// If, for some reason, you don't want this, you can run this function to prevent this.
     /// In that case, edits which would cause a resize will not occur.
@@ -205,7 +205,11 @@ impl<'ui, 'p, T: TextCallbackHandler> InputText<'ui, 'p, T> {
     }
 
     #[inline]
-    pub fn callback(mut self, callbacks: InputTextCallback, callback: T) -> InputText<'ui, 'p, T> {
+    pub fn callback<T2: InputTextCallbackHandler>(
+        mut self,
+        callbacks: InputTextCallback,
+        callback: T2,
+    ) -> InputText<'ui, 'p, T2> {
         if callbacks.contains(InputTextCallback::COMPLETION) {
             self.flags.insert(InputTextFlags::CALLBACK_COMPLETION);
         }
@@ -221,8 +225,14 @@ impl<'ui, 'p, T: TextCallbackHandler> InputText<'ui, 'p, T> {
         if callbacks.contains(InputTextCallback::EDIT) {
             self.flags.insert(InputTextFlags::CALLBACK_EDIT);
         }
-        self.callback_handler = callback;
-        self
+        InputText {
+            callback_handler: callback,
+            label: self.label,
+            hint: self.hint,
+            buf: self.buf,
+            flags: self.flags,
+            _phantom: self._phantom,
+        }
     }
 
     pub fn build(self) -> bool {
@@ -285,11 +295,11 @@ impl<'ui, 'p> InputTextMultiline<'ui, 'p, PassthroughCallback> {
     }
 }
 
-impl<'ui, 'p, T: TextCallbackHandler> InputTextMultiline<'ui, 'p, T> {
+impl<'ui, 'p, T: InputTextCallbackHandler> InputTextMultiline<'ui, 'p, T> {
     impl_text_flags!(InputText);
 
     /// By default (as of 0.8.0), imgui-rs will automatically handle string resizes
-    /// for `InputText` and `InputTextMultiline`.
+    /// for [InputText] and [InputTextMultiline].
     ///
     /// If, for some reason, you don't want this, you can run this function to prevent this.
     /// In that case, edits which would cause a resize will not occur.
@@ -544,7 +554,7 @@ bitflags!(
 ///
 /// Each method here lists the flag required to call it, and this module begins
 /// with an example of callbacks being used.
-pub trait TextCallbackHandler {
+pub trait InputTextCallbackHandler {
     /// Filters a char -- returning a `None` means that the char is removed,
     /// and returning another char substitutes it out.
     ///
@@ -743,15 +753,14 @@ impl<'a> TextCallbackData<'a> {
     /// at some byte pos.
     ///
     /// ## Panics
-    /// Panics if the `pos` is not a char boundary or if
-    /// there are not enough chars remaining.
+    /// Panics if the `pos` is not a char boundary.
     pub fn remove_chars(&mut self, pos: usize, char_count: usize) {
         let inner = &self.str()[pos..];
         let byte_count = inner
             .char_indices()
             .nth(char_count)
-            .expect("not enough characters in string")
-            .0;
+            .map(|v| v.0)
+            .unwrap_or(inner.len());
 
         unsafe {
             self.remove_chars_unchecked(pos, byte_count);
@@ -798,7 +807,7 @@ struct UserData<'a, T> {
 }
 
 /// This is our default callback.
-extern "C" fn callback<T: TextCallbackHandler>(
+extern "C" fn callback<T: InputTextCallbackHandler>(
     data: *mut sys::ImGuiInputTextCallbackData,
 ) -> c_int {
     struct CallbackData<'a, T> {
@@ -885,4 +894,4 @@ extern "C" fn callback<T: TextCallbackHandler>(
 /// If you do not set a callback handler, this will be used (but will never
 /// actually run, since you will not have pass imgui any flags).
 pub struct PassthroughCallback;
-impl TextCallbackHandler for PassthroughCallback {}
+impl InputTextCallbackHandler for PassthroughCallback {}