Added breakpoints code.

src/ui/breakpoint.c

@@ -0,0 +1,44 @@
+/**
+ * Copyright (c) 2021 Dominic Masters
+ * 
+ * This software is released under the MIT License.
+ * https://opensource.org/licenses/MIT
+ */
+
+#include "breakpoint.h"
+
+void breakpointListInit(breakpointlist_t *list) {
+  list->breakpointCount = 0;
+  list->user = NULL;
+  list->onBreakpoint = NULL;
+  list->breakpointCurrent = 0x00;
+}
+
+uint8_t breakpointGet(breakpointlist_t *list, float width) {
+  uint8_t bp, i;
+  bp = 0xFF;
+  for(i = 0; i < list->breakpointCount; i++) {
+    if(list->breakpoints[i] > width) break;
+    bp = i;
+  }
+  if(bp == 0xFF) bp = 0;
+  return bp;
+}
+
+void breakpointAdd(breakpointlist_t *list, float width) {
+  list->breakpoints[list->breakpointCount++] = width;
+}
+
+void breakpointResize(breakpointlist_t *list, float width) {
+  uint8_t bp;
+
+  // Determine breakpoint
+  bp = breakpointGet(list, width);
+  if(list->breakpointCurrent == bp) return;
+  list->breakpointCurrent = bp;
+
+  // Fire event.
+  if(list->onBreakpoint != NULL) {
+    list->onBreakpoint(list->user, bp, list->breakpoints[bp]);
+  }
+}

src/ui/breakpoint.h

@@ -0,0 +1,39 @@
+// Copyright (c) 2021 Dominic Masters
+// 
+// This software is released under the MIT License.
+// https://opensource.org/licenses/MIT
+
+#pragma once
+#include <dawn/dawn.h>
+
+/**
+ * Initialize a breakpoint.
+ * 
+ * @param list List to initialize.
+ */
+void breakpointInit(breakpointlist_t *list);
+
+/**
+ * Get the breakpoint for a given width set.
+ * 
+ * @param list List to get from.
+ * @param width Width to use.
+ * @return The breakpoint (index) for this screen size.
+ */
+uint8_t breakpointGet(breakpointlist_t *list, float width);
+
+/**
+ * Add a breakpoint definition to a breakpoint list.
+ * 
+ * @param list List to add to.
+ * @param width Width of the breakpoint.
+ */
+void breakpointAdd(breakpointlist_t *list, float width);
+
+/**
+ * Resize a breakpoint list, which (in turn) will fire the necessary events.
+ * 
+ * @param list List to resize.
+ * @param width Width to use.
+ */
+void breakpointResize(breakpointlist_t *list, float width);