From 39c1761380ed3f25eaf639e899ef1f710bcb83d3 Mon Sep 17 00:00:00 2001
From: James Magahern <james@magahern.com>
Date: Wed, 16 Jan 2019 10:52:37 -0800
Subject: Some organization and fading cursor

---
 buzzsaver.c | 165 +++++++++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 125 insertions(+), 40 deletions(-)

diff --git a/buzzsaver.c b/buzzsaver.c
index 7f24f5b..163c95e 100644
--- a/buzzsaver.c
+++ b/buzzsaver.c
@@ -14,6 +14,19 @@
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
 
+int __width, __height;
+static Window __window = { 0 };
+static Display *__display = NULL;
+
+static const double kLogoBackgroundWidth = 300.0;
+
+typedef struct {
+    cairo_t *ctx;
+
+    double cursor_opacity;
+    double cursor_fade_direction;
+} saver_state_t;
+
 int poll_events(Display *display, Window window)
 {
     const bool block_for_next_event = false;
@@ -42,43 +55,134 @@ int poll_events(Display *display, Window window)
     }
 }
 
+/*
+ * Scene specific stuff
+ */
+
+void draw_logo(saver_state_t *state)
+{
+    cairo_t *cr = state->ctx;
+    cairo_set_source_rgb(cr, (208.0 / 255.0), (69.0 / 255.0), (255.0 / 255.0));
+    cairo_rectangle(cr, 0, 0, kLogoBackgroundWidth, __height);
+    cairo_fill(cr);
+}
+
+void draw_password_field(saver_state_t *state)
+{
+    cairo_t *cr = state->ctx;
+    cairo_set_source_rgba(cr, 1.0, 1.0, 1.0, state->cursor_opacity);
+
+    const double cursor_height = 50.0;
+    const double cursor_width  = 30.0;
+    cairo_rectangle(cr, kLogoBackgroundWidth + 50.0, (__height - cursor_height) / 2.0, cursor_width, cursor_height);
+
+    cairo_fill(cr);
+}
+
+/*
+ * Main drawing/update routines 
+ */
+
+void update(saver_state_t *state)
+{
+    const double cursor_fade_speed = 0.007;
+    if (state->cursor_fade_direction > 0) {
+        state->cursor_opacity += cursor_fade_speed;
+        if (state->cursor_opacity > 1.0) {
+            state->cursor_fade_direction *= -1;
+        }
+    } else {
+        state->cursor_opacity -= cursor_fade_speed;
+        if (state->cursor_opacity <= 0.0) {
+            state->cursor_fade_direction *= -1;
+        }
+    }
+
+
+    poll_events(__display, __window);
+}
+
+void draw(saver_state_t *state)
+{
+    // Draw background
+    cairo_t *cr = state->ctx;
+    cairo_set_source_rgba(cr, 0.0, 0.0, 0.0, 1.0);
+    cairo_paint(cr);
+
+    draw_logo(state);
+    draw_password_field(state);
+}
+
+int runloop(cairo_surface_t *surface)
+{
+    cairo_t *cr = cairo_create(surface);
+
+    saver_state_t state = { 0 };
+    state.ctx = cr;
+    state.cursor_opacity = 1.0;
+    state.cursor_fade_direction = -1.0;
+
+    // Main run loop
+    struct timespec sleep_time = { 0, 5000000 };
+    for (;;) {
+        update(&state);
+
+        cairo_push_group(cr);
+        
+        draw(&state);
+        
+        cairo_pop_group_to_source(cr);
+
+        cairo_paint(cr);
+        cairo_surface_flush(surface);
+
+        nanosleep(&sleep_time, NULL);
+    }
+
+    // Cleanup
+    cairo_destroy(cr);
+
+    return EXIT_SUCCESS;
+}
+
 int main(int argc, char **argv)
 {
-    int width = 300;
-    int height = 300;
+    __width = 800;
+    __height = 600;
 
-    Display *display = XOpenDisplay(NULL);
-    if (display == NULL) {
+    __display = XOpenDisplay(NULL);
+    if (__display == NULL) {
         fprintf(stderr, "Error opening display\n");
         exit(1);
     }
 
-    Window root_window = DefaultRootWindow(display);
-    Window window = XCreateSimpleWindow(
-            display,        // display
+    Window root_window = DefaultRootWindow(__display);
+    __window = XCreateSimpleWindow(
+            __display,      // display
             root_window,    // parent window
             0, 0,           // x, y
-            width, height,  // width, height
+            __width,        // width
+            __height,       // height
             0,              // border_width
             0,              // border
             0               // background
     );
 
     // Enable key events
-    XSelectInput(display, window, ButtonPressMask | KeyPressMask | StructureNotifyMask);
+    XSelectInput(__display, __window, ButtonPressMask | KeyPressMask | StructureNotifyMask);
 
     // Map window to display
-    XMapWindow(display, window);
+    XMapWindow(__display, __window);
 
     // Create cairo surface
-    int screen = DefaultScreen(display);
-    Visual *visual = DefaultVisual(display, screen);
+    int screen = DefaultScreen(__display);
+    Visual *visual = DefaultVisual(__display, screen);
     cairo_surface_t *surface = cairo_xlib_surface_create(
-            display, 
-            window,
+            __display, 
+            __window,
             visual, 
-            width, 
-            height
+            __width, 
+            __height
     );
 
     if (surface == NULL) {
@@ -87,32 +191,13 @@ int main(int argc, char **argv)
     }
 
     // Docs say this must be called whenever the size of the window changes
-    cairo_xlib_surface_set_size(surface, width, height);
+    cairo_xlib_surface_set_size(surface, __width, __height);
+    
+    int result = runloop(surface);
 
-    // Create cairo surface
-    cairo_t *cr = cairo_create(surface);
-
-    // Main run loop
-    struct timespec sleep_time = { 0, 5000000 };
-    for (;;) {
-        cairo_push_group(cr);
-        cairo_set_source_rgba(cr, 1.0, 0.0, 0.0, 1.0);
-        cairo_fill_preserve(cr);
-        cairo_paint(cr);
-        cairo_pop_group_to_source(cr);
-
-        cairo_paint(cr);
-        cairo_surface_flush(surface);
-
-        poll_events(display, window);
-        nanosleep(&sleep_time, NULL);
-    }
-
-    // Cleanup
-    cairo_destroy(cr);
     cairo_surface_destroy(surface);
-    XCloseDisplay(display);
+    XCloseDisplay(__display);
 
-    return 0;
+    return result;
 }
 
-- 
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