.gitignore

@@ -1 +1,2 @@
-builddir/
+ui
+

Makefile

@@ -0,0 +1,6 @@
+CFLAGS=-Wall -Wextra -std=c11 -pedantic `pkg-config --cflags cairo pangocairo`
+LIBS=`pkg-config --libs cairo pangocairo` -lX11
+
+ui: main.c
+	$(CC) $(CFLAGS) -o ui main.c $(LIBS)
+

main.c

@@ -0,0 +1,384 @@
+#include <X11/Xlib.h>
+#include <X11/Xatom.h>
+#include <X11/Xutil.h>
+#include <cairo.h>
+#include <cairo-xlib.h>
+#include <pango/pangocairo.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+
+#define M_PI 3.14159265358979323846
+
+typedef struct Vec2 {
+    double x, y;
+} Vec2;
+
+typedef struct RGB {
+    double r, g, b;
+} RGB;
+
+typedef struct uui_row {
+    Vec2 starting_position, position, spacing, element_size;
+    bool is_vertical;
+} uui_row_t;
+
+typedef struct uui_context {
+    int hot_id, active_id;
+    Vec2 mouse_pos;
+    bool mouse1_down;
+    cairo_t *cr;
+} uui_context_t;
+
+typedef enum {
+    TEXT_CENTER_ALIGN,
+    TEXT_CENTER_ALIGN_LEFT,
+} TextCenterAlign;
+
+typedef struct uui_text_style {
+    RGB text_color;
+    PangoFontDescription *font_description;
+    TextCenterAlign center_align;
+} uui_text_style_t;
+
+typedef struct uui_button_style {
+    RGB normal_color, hot_color, active_color;
+    double border_radius;
+    int do_fill;
+    uui_text_style_t *text_style;
+} uui_button_style_t;
+
+Vec2 vec2(double x, double y) {
+    return (Vec2) {
+        x, y
+    };
+}
+
+RGB rgb(double r, double g, double b) {
+    return (RGB) {
+        r, g, b
+    };
+}
+
+bool uui_collide_point_rect(Vec2 pos, Vec2 size, Vec2 point) {
+    return point.x >= pos.x && pos.x + size.x >= point.x &&
+        point.y >= pos.y && pos.y + size.y >= point.y;
+}
+
+void panic(int exit_code, const char *error) {
+    fputs(error, stderr);
+    exit(exit_code);
+}
+
+cairo_surface_t *create_x11_surface(int x, int y) {
+    Display *dsp;
+    Drawable da;
+    int screen;
+    cairo_surface_t *sfc;
+
+    if ((dsp = XOpenDisplay(NULL)) == NULL)
+        panic(1, "Failed to open display");
+
+    screen = DefaultScreen(dsp);
+    da = XCreateSimpleWindow(dsp, DefaultRootWindow(dsp), 0, 0, x, y, 0, 0, 0);
+    XSelectInput(dsp, da, ButtonPressMask | ButtonReleaseMask | KeyPressMask | PointerMotionMask);
+    XMapWindow(dsp, da);
+
+    sfc = cairo_xlib_surface_create(dsp, da, DefaultVisual(dsp, screen), x, y);
+    cairo_xlib_surface_set_size(sfc, x, y);
+
+    return sfc;
+}
+
+void destroy_x11_surface(cairo_surface_t *sfc) {
+    Display *dsp = cairo_xlib_surface_get_display(sfc);
+    cairo_surface_destroy(sfc);
+    XCloseDisplay(dsp);
+}
+
+void uui_handle_event(uui_context_t *uc, XEvent *e) {
+    char keybuf[8];
+    KeySym key;
+
+    switch (e->type) {
+        case ButtonPress:
+            if (e->xbutton.button == Button1)
+                uc->mouse1_down = true;
+            break;
+        case ButtonRelease:
+            if (e->xbutton.button == Button1)
+                uc->mouse1_down = false;
+            break;
+        case KeyPress:
+            XLookupString(&e->xkey, keybuf, sizeof(keybuf), &key, NULL);
+            break;
+        case MotionNotify:
+            uc->mouse_pos.x = e->xmotion.x;
+            uc->mouse_pos.y = e->xmotion.y;
+            break;
+    }
+}
+
+void uui_draw_rect(cairo_t *cr, Vec2 pos, Vec2 size, double border_radius)
+{
+    double x = pos.x;
+    double y = pos.y;
+    double width = size.x;
+    double height = size.y;
+    if (border_radius > 0) {
+        double aspect = 1.0;
+        double corner_radius = border_radius;
+        double radius = corner_radius / aspect;
+        double degrees = M_PI / 180.0;
+
+        cairo_new_sub_path(cr);
+        cairo_arc(cr, x + width - radius, y + radius, radius, -90 * degrees, 0 * degrees);
+        cairo_arc(cr, x + width - radius, y + height - radius, radius, 0 * degrees, 90 * degrees);
+        cairo_arc(cr, x + radius, y + height - radius, radius, 90 * degrees, 180 * degrees);
+        cairo_arc(cr, x + radius, y + radius, radius, 180 * degrees, 270 * degrees);
+        cairo_close_path(cr);
+    } else {
+        cairo_rectangle(cr, x, y, width, height);
+    }
+}
+
+void uui_draw_text(cairo_t *cr, PangoFontDescription *desc, Vec2 pos, const char *text) {
+    PangoLayout *layout = pango_cairo_create_layout(cr);
+    pango_layout_set_font_description(layout, desc);
+    pango_layout_set_text(layout, text, -1);
+    cairo_move_to(cr, pos.x, pos.y);
+    pango_cairo_show_layout(cr, layout);
+    g_object_unref(layout);
+}
+
+void uui_draw_centered_text(cairo_t *cr, PangoFontDescription *desc, TextCenterAlign align, Vec2 rect_pos, Vec2 rect_size, const char *text) {
+    PangoLayout *layout = pango_cairo_create_layout(cr);
+    int font_width;
+    int font_height;
+
+    pango_layout_set_font_description(layout, desc);
+    pango_layout_set_text(layout, text, -1);
+    pango_layout_get_pixel_size(layout, &font_width, &font_height);
+
+    double x = rect_pos.x + ((rect_size.x - font_width) / 2);
+    double y = rect_pos.y + ((rect_size.y - font_height) / 2);
+    
+    if (align == TEXT_CENTER_ALIGN_LEFT) {
+        // center the text only horizontally and add a hardcoded padding to the x position
+        // TODO: unhardcode the padding
+        x = rect_pos.x + 4;
+    }
+
+    cairo_move_to(cr, x, y);
+    pango_cairo_show_layout(cr, layout);
+    g_object_unref(layout);
+}
+
+bool uui_do_click_region(uui_context_t *uc, Vec2 pos, Vec2 size, int id) {
+    if (id != -1) {
+        /* if the element is hot (hovered) and mouse button 1 is down, it's clicked */
+        if (uc->hot_id == id && uc->mouse1_down) {
+            /* this function only ever returns true once - when the click happens (unless id == -1, in which case it's checked each time, see below) */
+            if (uc->active_id == id) {
+                return false;
+            }
+            uc->active_id = id;
+            return true;
+        } else {
+            uc->active_id = -1;
+            return false;
+        }
+    } else {
+        /* if the user provided -1 as an id, we will do the check independently of the hot/active system */
+        return uc->mouse1_down && uui_collide_point_rect(pos, size, uc->mouse_pos);
+    }
+}
+
+bool uui_do_hover_region(uui_context_t *uc, Vec2 pos, Vec2 size, int id) {
+    if (id != -1) {
+        if (uui_collide_point_rect(pos, size, uc->mouse_pos)) {
+            uc->hot_id = id;
+            return true;
+        } else {
+            uc->hot_id = -1;
+            return false;
+        }
+    } else {
+        /* if the user provided -1 as an id, we will do the check independently of the hot/active system */
+        return uui_collide_point_rect(pos, size, uc->mouse_pos);
+    }
+}
+
+void uui_do_text(uui_context_t *uc, uui_text_style_t *style, Vec2 pos, const char *text) {
+    cairo_save(uc->cr);
+
+    cairo_set_source_rgb(uc->cr, style->text_color.r, style->text_color.g, style->text_color.b);
+    uui_draw_text(uc->cr, style->font_description, pos, text);
+    cairo_fill(uc->cr);
+
+    cairo_restore(uc->cr);
+}
+
+void uui_do_centered_text(uui_context_t *uc, uui_text_style_t *style, Vec2 pos, Vec2 size, const char *text) {
+    cairo_save(uc->cr);
+
+    cairo_set_source_rgb(uc->cr, style->text_color.r, style->text_color.g, style->text_color.b);
+    uui_draw_centered_text(uc->cr, style->font_description, style->center_align, pos, size, text);
+    cairo_fill(uc->cr);
+
+    cairo_restore(uc->cr);
+}
+
+bool uui_do_button(uui_context_t *uc, uui_button_style_t *style, Vec2 pos, Vec2 size, const char *text, int id) {
+    bool clicked = false;
+
+    cairo_save(uc->cr);
+
+    if (uui_do_hover_region(uc, pos, size, id)) {
+        cairo_set_source_rgb(uc->cr, style->hot_color.r, style->hot_color.g, style->hot_color.b);
+        if (uui_do_click_region(uc, pos, size, id)) {
+            cairo_set_source_rgb(uc->cr, style->active_color.r, style->active_color.g, style->active_color.b);
+            clicked = true;
+        }
+    } else {
+        cairo_set_source_rgb(uc->cr, style->normal_color.r, style->normal_color.g, style->normal_color.b);
+    }
+
+    uui_draw_rect(uc->cr, pos, size, style->border_radius);
+
+    if (style->do_fill) {
+        cairo_fill(uc->cr);
+    } else {
+        cairo_stroke(uc->cr);
+    }
+
+    if (text != NULL) {
+        uui_do_centered_text(uc, style->text_style, pos, size, text);
+    }
+
+    cairo_restore(uc->cr);
+
+    return clicked;
+}
+
+uui_context_t *uui_context_create(cairo_t *cr) {
+    uui_context_t *uc = malloc(sizeof(uui_context_t));
+    uc->mouse_pos = vec2(0, 0);
+    uc->mouse1_down = false;
+    uc->cr = cr;
+    return uc;
+}
+
+void uui_context_destroy(uui_context_t *uc) {
+    free(uc);
+}
+
+void uui_row_start(uui_row_t *row) {
+    row->position = row->starting_position;
+}
+
+void uui_row_advance(uui_row_t *row, Vec2 add) {
+    /* advance the position, respecting the spacing, regardless of direction */
+    row->position.x += add.x + row->spacing.x;
+    row->position.y += add.y + row->spacing.y;
+}
+
+void uui_row_element(uui_row_t *row) {
+    /* increment position based on element size */
+    /* the spacing is added regardless of the direction */
+    if (row->is_vertical) { 
+        row->position.y += row->element_size.y;
+    } else {
+        row->position.x += row->element_size.x;
+    }
+    row->position.x += row->spacing.x;
+    row->position.y += row->spacing.y;
+}
+
+int main(void) {
+    cairo_surface_t *sfc = create_x11_surface(800, 600);
+    cairo_t *cr = cairo_create(sfc);
+    PangoFontDescription *font_description = pango_font_description_new();
+    uui_context_t *uc = uui_context_create(cr);
+    uui_button_style_t button_style;
+    uui_text_style_t text_style;
+    uui_row_t row;
+
+    XEvent e;
+
+    pango_font_description_set_family(font_description, "sans-serif");
+    pango_font_description_set_weight(font_description, PANGO_WEIGHT_NORMAL);
+    pango_font_description_set_absolute_size(font_description, 16 * PANGO_SCALE);
+
+    button_style.border_radius = 8;
+    button_style.do_fill = 1;
+    button_style.normal_color = rgb(1.0, 0.0, 0.0);
+    button_style.hot_color = rgb(0.0, 1.0, 0.0);
+    button_style.active_color = rgb(0.0, 0.0, 1.0);
+    button_style.text_style = &text_style;
+
+    text_style.text_color = rgb(1.0, 1.0, 1.0);
+    text_style.font_description = font_description;
+    text_style.center_align = TEXT_CENTER_ALIGN_LEFT; 
+
+    row.starting_position = vec2(20.0, 20.0);
+    row.position = vec2(0.0, 0.0);
+    row.spacing = vec2(20.0, 0.0);
+    row.element_size = vec2(100.0, 30.0);
+    row.is_vertical = false;
+
+    int selected_tab = 0;
+
+    for (;;) {
+        XNextEvent(cairo_xlib_surface_get_display(sfc), &e);
+        uui_handle_event(uc, &e);
+
+        cairo_set_source_rgb(cr, 0.0, 0.0, 0.0);
+        cairo_paint(cr);
+
+        uui_row_start(&row);
+        if (uui_do_button(uc, &button_style, row.position, row.element_size, "one", 0)) {
+            selected_tab = 0;
+        }
+        uui_row_element(&row);
+        if (uui_do_button(uc, &button_style, row.position, row.element_size, "two", 1)) {
+            selected_tab = 1;
+        }
+        uui_row_element(&row);
+        if (uui_do_button(uc, &button_style, row.position, row.element_size, "three", 2)) {
+            selected_tab = 2;
+        }
+        uui_row_element(&row);
+        if (uui_do_button(uc, &button_style, row.position, row.element_size, "four", 3)) {
+            selected_tab = 3;
+        }
+        uui_row_element(&row);
+
+        char *text = "no tab selected";
+
+        switch (selected_tab) {
+            case 0:
+                text = "tab 1";
+                break;
+            case 1:
+                text = "tab 2";
+                break;
+            case 2:
+                text = "tab 3";
+                break;
+            case 3:
+                text = "tab 4";
+                break;
+        }
+
+        uui_do_text(uc, &text_style, row.position, text);
+    }
+
+    pango_font_description_free(font_description);
+    cairo_destroy(cr);
+    destroy_x11_surface(sfc);
+    uui_context_destroy(uc);
+    return 0;
+}
+

meson.build

@@ -1,8 +0,0 @@
-project('blit', 'cpp')
-
-
-cairomm_dep = dependency('cairomm-1.0')
-pangocairo_dep = dependency('pangocairo')
-xlib_dep = dependency('x11')
-
-executable('blit_app', './src/main.cpp', dependencies : [cairomm_dep, xlib_dep, pangocairo_dep])

src/main.cpp

@@ -1,342 +0,0 @@
-#include <string>
-#include <vector>
-#include <iostream>
-#include <cairomm-1.0/cairomm/xlib_surface.h>
-#include <cairomm-1.0/cairomm/context.h>
-#include <cairomm-1.0/cairomm/surface.h>
-#include <pango/pangocairo.h>
-
-
-void panic(int exit_code, const char *message) {
-    fputs(message, stderr);
-    exit(exit_code);
-}
-
-namespace Blit {
-
-bool collide_point_rect(double x, double y, double w, double h, double x1, double y1) {
-    return x1 >= x && x + w >= x1 &&
-        y1 >= y && y + h >= y1;
-}
-
-
-enum TextAlign {
-    TEXT_ALIGN_NONE,
-    TEXT_ALIGN_CENTER_LEFT,
-    TEXT_ALIGN_CENTER
-};
-
-
-class RGB {
-public:
-    double r, g, b;
-public:
-    RGB(double r, double g, double b) : r(r), g(g), b(b) {
-
-    }
-};
-
-
-class BaseElement {
-public:
-    BaseElement() {}
-    virtual ~BaseElement() {}
-
-    bool should_get_x_events = true;
-    virtual void draw() = 0;
-    virtual void handle_event(XEvent *e) = 0;
-};
-
-
-class Window {
-public:
-    Cairo::RefPtr<Cairo::Context> cr;
-    Display *dsp;
-private:
-    std::vector<Blit::BaseElement *> m_attached_elements;
-public:
-    Window(int x, int y)
-    {
-        Drawable da;
-        int screen;
-
-        if ((dsp = XOpenDisplay(NULL)) == NULL)
-            panic(1, "Failed to open display");
-
-        screen = DefaultScreen(dsp);
-        da = XCreateSimpleWindow(dsp, DefaultRootWindow(dsp), 0, 0, x, y, 0, 0, 0);
-        XSelectInput(dsp, da, ButtonPressMask | ButtonReleaseMask | KeyPressMask | PointerMotionMask);
-        XMapWindow(dsp, da);
-
-        auto x_surface = Cairo::XlibSurface::create(
-            dsp,
-            da,
-            DefaultVisual(dsp, screen),
-            x,
-            y
-        );
-        cr = Cairo::Context::create(x_surface);
-    }
-
-    void attach_element_init(Blit::BaseElement *element) {
-        m_attached_elements.push_back(element);
-    }
-
-    void attach_element(Blit::BaseElement *element) {
-        m_attached_elements.push_back(element);
-        element->draw();
-    }
-
-    void redraw_all() {
-        for (Blit::BaseElement * element : m_attached_elements) {
-            element->draw();
-        }
-    }
-
-    void handle_x_event(XEvent *e) {
-        for (Blit::BaseElement * element : m_attached_elements) {
-            if (element->should_get_x_events)
-                element->handle_event(e);
-        }
-    }
-};
-
-
-class Text : public BaseElement {
-public:
-    PangoFontDescription *font_description;
-    bool should_get_x_events = false;
-    Blit::TextAlign text_align = Blit::TextAlign::TEXT_ALIGN_NONE;
-    double x, y, box_x, box_y, box_w, box_h = 0;
-    std::string text;
-    Blit::RGB fg;
-
-    Cairo::RefPtr<Cairo::Context> cr;
-public:
-    Text(Cairo::RefPtr<Cairo::Context> cr, std::string& text, PangoFontDescription *font_description) :
-        cr(cr),
-        text(text),
-        font_description(font_description),
-        fg(0.0, 0.0, 0.0)
-    {}
-
-    virtual ~Text() {}
-
-    void draw() {
-        cr->save();
-        cr->set_source_rgb(fg.r, fg.g, fg.b);
-
-        if (text_align == Blit::TextAlign::TEXT_ALIGN_NONE) {
-            PangoLayout *layout = pango_cairo_create_layout(cr->cobj());
-            pango_layout_set_font_description(layout, font_description);
-            pango_layout_set_text(layout, text.c_str(), -1);
-            cr->move_to(x, y);
-            pango_cairo_show_layout(cr->cobj(), layout);
-            g_object_unref(layout);
-        } else if (text_align == Blit::TextAlign::TEXT_ALIGN_CENTER_LEFT) {
-            PangoLayout *layout = pango_cairo_create_layout(cr->cobj());
-            int font_width;
-            int font_height;
-
-            pango_layout_set_font_description(layout, font_description);
-            pango_layout_set_text(layout, text.c_str(), -1);
-            pango_layout_get_pixel_size(layout, &font_width, &font_height);
-
-            double x = box_x + ((box_w - font_width) / 2);
-            double y = box_y + ((box_h - font_height) / 2);
-
-            // TODO: unhardcode the padding
-            x = box_x + 4;
-
-            cr->move_to(x, y);
-            pango_cairo_show_layout(cr->cobj(), layout);
-            g_object_unref(layout);
-        } else if (text_align == Blit::TextAlign::TEXT_ALIGN_CENTER) {
-            PangoLayout *layout = pango_cairo_create_layout(cr->cobj());
-            int font_width;
-            int font_height;
-
-            pango_layout_set_font_description(layout, font_description);
-            pango_layout_set_text(layout, text.c_str(), -1);
-            pango_layout_get_pixel_size(layout, &font_width, &font_height);
-
-            double x = box_x + ((box_w - font_width) / 2);
-            double y = box_y + ((box_h - font_height) / 2);
-
-            cr->move_to(x, y);
-            pango_cairo_show_layout(cr->cobj(), layout);
-            g_object_unref(layout);
-        }
-
-        cr->fill();
-        cr->restore();
-    }
-
-    void handle_event(XEvent *e) {}
-
-    void set_x(double val) {
-        x = val;
-        draw();
-    }
-    void set_y(double val) {
-        y = val;
-        draw();
-    }
-    void set_box_x(double val) {
-        box_x = val;
-        draw();
-    }
-    void set_box_y(double val) {
-        box_y = val;
-        draw();
-    }
-    void set_box_w(double val) {
-        box_w = val;
-        draw();
-    }
-    void set_box_h(double val) {
-        box_h = val;
-        draw();
-    }
-    void set_text(std::string& text) {
-        text = text;
-        draw();
-    }
-    void set_text_align(Blit::TextAlign val) {
-        text_align = val;
-        draw();
-    }
-    void set_current_fg(Blit::RGB val) {
-        fg = val;
-        draw();
-    }
-};
-
-
-class Button : public BaseElement {
-public:
-    bool should_get_x_events = true;
-    double x, y, w, h, border_radius = 0;
-    Blit::RGB current_bg, bg, sel_bg;
-
-    bool is_hot, is_active = false;
-
-    Cairo::RefPtr<Cairo::Context> cr;
-public:
-    Button(Cairo::RefPtr<Cairo::Context> cr) :
-        should_get_x_events(true),
-        current_bg(0.0, 0.0, 0.0),
-        sel_bg(0.0, 0.0, 0.0),
-        bg(0.0, 0.0, 0.0),
-        cr(cr)
-    {}
-
-    virtual ~Button() {}
-
-    void draw() {
-        cr->save();
-        cr->set_source_rgb(current_bg.r, current_bg.g, current_bg.b);
-        if (border_radius > 0) {
-            double aspect = 1.0;
-            double radius = border_radius / aspect;
-            double degrees = M_PI / 180.0;
-
-            cr->begin_new_sub_path();
-            cr->arc(x + w - radius, y + radius, radius, -90 * degrees, 0 * degrees);
-            cr->arc(x + w - radius, y + h - radius, radius, 0 * degrees, 90 * degrees);
-            cr->arc(x + radius, y + h - radius, radius, 90 * degrees, 180 * degrees);
-            cr->arc(x + radius, y + radius, radius, 180 * degrees, 270 * degrees);
-            cr->close_path();
-        } else {
-            cr->rectangle(x, y, w, h);
-        }
-        cr->fill();
-        cr->restore();
-    }
-
-    void handle_event(XEvent *e) {
-        char keybuf[8];
-        KeySym key;
-
-        switch (e->type) {
-            case MotionNotify:
-                bool is_hot_now = Blit::collide_point_rect(x, y, w, h, e->xmotion.x, e->xmotion.y);
-                if (!is_hot && is_hot_now) { // just became hot
-                    set_current_bg(sel_bg);
-                    is_hot = true;
-                } else if (is_hot && !is_hot_now) { // just became not hot
-                    set_current_bg(bg);
-                    is_hot = false;
-                }
-                break;
-        }
-    }
-
-    void set_x(double val) {
-        x = val;
-        draw();
-    }
-    void set_y(double val) {
-        y = val;
-        draw();
-    }
-    void set_w(double val) {
-        w = val;
-        draw();
-    }
-    void set_h(double val) {
-        h = val;
-        draw();
-    }
-    void set_border_radius(double val) {
-        border_radius = val;
-        draw();
-    }
-    void set_current_bg(Blit::RGB val) {
-        current_bg = val;
-        draw();
-    }
-};
-
-}
-
-int main() {
-    std::string text = "click me now";
-    XEvent e;
-    PangoFontDescription *font_description = pango_font_description_new();
-
-    pango_font_description_set_family(font_description, "sans-serif");
-    pango_font_description_set_weight(font_description, PANGO_WEIGHT_NORMAL);
-    pango_font_description_set_absolute_size(font_description, 16 * PANGO_SCALE);
-
-    Blit::Window window(800, 600);
-    Blit::Button button(window.cr);
-    Blit::Text button_text(window.cr, text, font_description);
-
-    button.x = 20.0;
-    button.y = 20.0;
-    button.w = 100.0;
-    button.h = 30.0;
-    button.border_radius = 0.0;
-    button.bg = Blit::RGB(1.0, 0.0, 0.0);
-    button.sel_bg = Blit::RGB(0.0, 1.0, 0.0);
-
-    button_text.x = button.x;
-    button_text.y = button.y;
-    button_text.box_x = button.x;
-    button_text.box_y = button.y;
-    button_text.box_w = button.w;
-    button_text.box_h = button.h;
-    button_text.fg = Blit::RGB(1.0, 1.0, 1.0);
-    button_text.text_align = Blit::TextAlign::TEXT_ALIGN_CENTER;
-    
-    window.attach_element(&button);
-    window.attach_element(&button_text);
-
-    for (;;) {
-        XNextEvent(window.dsp, &e);
-        window.handle_x_event(&e);
-    }
-
-    return 0;
-}