Add entry with basic text editing and validation for numbers

src/gui/Entry.cpp

@@ -0,0 +1,121 @@
+#include "../../include/gui/Entry.hpp"
+#include "../../include/gui/Utils.hpp"
+#include "../../include/Theme.hpp"
+#include <mglpp/graphics/Rectangle.hpp>
+#include <mglpp/window/Window.hpp>
+#include <mglpp/window/Event.hpp>
+#include <mglpp/system/FloatRect.hpp>
+#include <mglpp/system/Utf8.hpp>
+#include <optional>
+
+namespace gsr {
+    static const float padding_top = 10.0f;
+    static const float padding_bottom = 10.0f;
+    static const float padding_left = 10.0f;
+    static const float padding_right = 10.0f;
+
+    Entry::Entry(mgl::Font *font, const char *text, float max_width) : text("", *font), max_width(max_width) {
+        this->text.set_color(get_theme().text_color);
+        set_string(text);
+    }
+
+    bool Entry::on_event(mgl::Event &event, mgl::Window&, mgl::vec2f offset) {
+        if(event.type == mgl::Event::MouseButtonPressed) {
+            selected = mgl::FloatRect(position + offset, get_size()).contains({ (float)event.mouse_button.x, (float)event.mouse_button.y });
+        } else if(event.type == mgl::Event::KeyPressed && selected) {
+            if(event.key.code == mgl::Keyboard::Backspace && !text.get_string().empty()) {
+                std::string str = text.get_string();
+                const size_t prev_index = mgl::utf8_get_start_of_codepoint((const unsigned char*)str.c_str(), str.size(), str.size());
+                str.erase(prev_index, std::string::npos);
+                set_string(std::move(str));
+            }
+        } else if(event.type == mgl::Event::TextEntered && selected && event.text.codepoint >= 32) {
+            std::string str = text.get_string();
+            str.append(event.text.str, event.text.size);
+            set_string(std::move(str));
+        }
+        return true;
+    }
+
+    void Entry::draw(mgl::Window &window, mgl::vec2f offset) {
+        const mgl::vec2f draw_pos = position + offset;
+
+        mgl::Rectangle background(get_size());
+        background.set_position(draw_pos.floor());
+        background.set_color(selected ? mgl::Color(0, 0, 0, 255) : mgl::Color(0, 0, 0, 120));
+        window.draw(background);
+
+        if(selected) {
+            const int border_size = 3;
+            draw_rectangle_outline(window, draw_pos.floor(), get_size().floor(), get_theme().tint_color, border_size);
+
+            const int caret_width = 2;
+            mgl::Rectangle caret({caret_width, text.get_bounds().size.y});
+            caret.set_position((draw_pos + mgl::vec2f(padding_left + caret_offset_x, padding_top)).floor());
+            caret.set_color(mgl::Color(255, 255, 255));
+            window.draw(caret);
+        }
+
+        text.set_position((draw_pos + mgl::vec2f(padding_left, get_size().y * 0.5f - text.get_bounds().size.y * 0.5f)).floor());
+        window.draw(text);
+    }
+
+    mgl::vec2f Entry::get_size() {
+        return { max_width, text.get_bounds().size.y + padding_top + padding_bottom };
+    }
+
+    void Entry::set_string(std::string str) {
+        if(!validate_handler || validate_handler(str)) {
+            text.set_string(std::move(str));
+            caret_offset_x = text.find_character_pos(99999).x - this->text.get_position().x;
+            fprintf(stderr, "caret offset: %f\n", caret_offset_x);
+        }
+    }
+
+    static bool is_number(uint8_t c) {
+        return c >= '0' && c <= '9';
+    }
+
+    static std::optional<int> to_integer(const std::string &str) {
+        if(str.empty())
+            return std::nullopt;
+
+        size_t i = 0;
+        const bool negative = str[0] == '-';
+        if(negative)
+            i = 1;
+
+        int number = 0;
+        for(; i < str.size(); ++i) {
+            if(!is_number(str[i]))
+                return false;
+
+            const int new_number = number * 10 + (str[i] - '0');
+            if(new_number < number)
+                return std::nullopt; // Overflow
+            number = new_number;
+        }
+        
+        if(negative)
+            number = -number;
+
+        return number;
+    }
+
+    EntryValidateHandler create_entry_validator_integer_in_range(int min, int max) {
+        return [min, max](std::string &str) {
+            if(str.empty())
+                return true;
+
+            std::optional<int> number = to_integer(str);
+            if(!number)
+                return false;
+
+            if(number.value() < min)
+                str = std::to_string(min);
+            else if(number.value() > max)
+                str = std::to_string(max);
+            return true;
+        };
+    }
+}