[ui] add reflowing layout helpers

Author: okay

src/rmkit/ui/layouts.cpy

@@ -15,10 +15,11 @@ namespace ui:
     Layout(int x, y, w, h, Scene s): x(x), y(y), w(w), h(h), scene(s):
       pass
 
-    void add(Widget *w):
+    shared_ptr<Widget> add(Widget *w):
       sp := shared_ptr<Widget>(w)
       children.push_back(sp)
       scene->add(sp)
+      return sp
 
     void hide():
       for auto w: children:
@@ -74,7 +75,7 @@ namespace ui:
   // the vertical layout is used for packing widgets
   // vertically (top to bottom). it implements only 3 functions: pack_start,
   // pack_end and pack_center
-  // 
+  //
   class VerticalLayout: public AutoLayout:
     public:
     using AutoLayout::pack_start
@@ -220,3 +221,4 @@ namespace ui:
         padding_x = leftover / 2
       w.x = self.x + padding_x
       w.y += self.y
+

src/rmkit/ui/main_loop.cpy

@@ -28,6 +28,7 @@
 #include "widget.h"
 #include "task_queue.h"
 #include "timer.h"
+#include "../ui/reflow.h"
 
 #include <unistd.h>
 
@@ -219,6 +220,25 @@ namespace ui:
         for auto s : scene_stack:
           s->redraw()
 
+    static void reflow(Scene s):
+      layouts := ReflowLayout::scene_to_layouts.find(s)
+      if layouts == ReflowLayout::scene_to_layouts.end():
+        return
+
+      for auto w : s->widgets:
+        w->restore_coords()
+
+      unordered_map<ReflowLayout*, bool> has_parent;
+      for auto l : layouts->second:
+        l->restore_coords()
+        for auto w : l->children:
+          w->restore_coords()
+        l->mark_children(has_parent)
+
+      for auto l : layouts->second:
+        if has_parent.find(l) == has_parent.end():
+          l->reflow()
+
 
     /// blocking read for input
     static void read_input(int timeout_ms=0):
@@ -240,6 +260,10 @@ namespace ui:
           if s->clear_under:
             break
 
+      reflow(scene)
+      for auto &sc : scene_stack:
+        reflow(sc)
+
     // function: set_scene
     // set the main scene for the app to display when drawing
     static void set_scene(Scene s):

src/rmkit/ui/reflow.cpy

@@ -0,0 +1,198 @@
+#include "layouts.h"
+
+#define RANGE(X) X.begin(), X.end()
+namespace ui:
+  class ReflowLayout: public ui::Layout:
+    public:
+    static unordered_map<Scene, vector<ReflowLayout*>> scene_to_layouts
+    vector<ReflowLayout*> layouts
+
+    class PackedChild:
+      public:
+      shared_ptr<ReflowLayout> sl
+      shared_ptr<Widget> sp
+      int padding
+    ;
+
+    vector<PackedChild> start
+    vector<PackedChild> end
+    vector<PackedChild> center
+
+    int _x, _y, _w, _h
+
+    ReflowLayout(int x, y, w, h, Scene s): Layout(x,y,w,h,s), _x(x), _y(y), _w(w), _h(h):
+      if scene_to_layouts.find(scene) == scene_to_layouts.end():
+        scene_to_layouts[s] = {}
+      scene_to_layouts[s].push_back(self)
+
+
+    ~ReflowLayout():
+      if scene_to_layouts.find(scene) != scene_to_layouts.end():
+        it := find(RANGE(scene_to_layouts[scene]), self)
+        if it == scene_to_layouts[scene].end():
+          return
+
+        scene_to_layouts[scene].erase(it)
+
+    void restore_coords():
+      x = _x
+      y = _y
+      w = _w
+      h = _h
+
+    virtual void reflow():
+      pass
+
+    shared_ptr<ReflowLayout> add(ReflowLayout *l):
+      sp := shared_ptr<ReflowLayout>(l)
+      return sp
+
+    void mark_children(unordered_map<ReflowLayout*, bool> &has_parent):
+      for auto l : self.layouts:
+        has_parent[l] = true
+        l->mark_children(has_parent)
+
+    void pack_start(Widget* w, int padding=0):
+      sp := Layout::add(w)
+      self.start.push_back({NULL, sp, padding})
+    void pack_end(Widget* w, int padding=0):
+      sp := Layout::add(w)
+      self.end.push_back({NULL, sp, padding})
+    void pack_center(Widget* w, int padding=0):
+      sp := Layout::add(w)
+      self.center.push_back({NULL, sp, padding})
+
+    void pack_start(ReflowLayout* w, int padding=0):
+      layouts.push_back(w)
+      sl := ReflowLayout::add(w)
+      self.start.push_back({sl, NULL, padding})
+    void pack_end(ReflowLayout* w, int padding=0):
+      layouts.push_back(w)
+      sl := ReflowLayout::add(w)
+      self.end.push_back({sl, NULL, padding})
+    void pack_center(ReflowLayout* w, int padding=0):
+      layouts.push_back(w)
+      sl := ReflowLayout::add(w)
+      self.center.push_back({sl, NULL, padding})
+  ;
+  unordered_map<Scene, vector<ReflowLayout*>> ReflowLayout::scene_to_layouts = {}
+
+  class HorizontalReflow: public ReflowLayout:
+    public:
+    using ReflowLayout::pack_start;
+    using ReflowLayout::pack_end;
+    using ReflowLayout::pack_center;
+
+    HorizontalReflow(int x, y, w, h, Scene s): ReflowLayout(x,y,w,h,s):
+      pass
+
+    void reflow():
+      offset := 0
+      debug "REFLOWING HORIZONTAL"
+      for auto pw : self.start:
+        if pw.sp != NULL:
+          padding = pw.padding
+          pw.sp->x += offset + self.x + padding
+          pw.sp->y += self.y
+          offset += pw.sp->w + padding
+          pw.sp->on_reflow()
+        if pw.sl != NULL:
+          padding = pw.padding
+          pw.sl->x += offset + self.x + padding
+          pw.sl->y += self.y
+          offset += pw.sl->w + padding
+          pw.sl->reflow()
+
+      offset = self.w
+      for auto pw : self.end:
+        if pw.sp != NULL:
+          padding = pw.padding
+          pw.sp->x = self.x + offset - pw.sp->w - padding
+          pw.sp->y += self.y
+          offset -= pw.sp->w + padding
+          pw.sp->on_reflow()
+        if pw.sl != NULL:
+          padding = pw.padding
+          pw.sl->x = self.x + offset - pw.sl->w - padding
+          pw.sl->y += self.y
+          offset -= pw.sl->w + padding
+          pw.sl->reflow()
+
+      for auto pw : self.center:
+        if pw.sp != NULL:
+          leftover := self.w - pw.sp->w
+          padding_x := 0
+          if leftover > 0:
+            padding_x = leftover / 2
+          pw.sp->x = self.x + padding_x
+          pw.sp->y += self.y
+          pw.sp->on_reflow()
+        if pw.sl != NULL:
+          leftover := self.w - pw.sl->w
+          padding_x := 0
+          if leftover > 0:
+            padding_x = leftover / 2
+          pw.sl->x = self.x + padding_x
+          pw.sl->y += self.y
+          pw.sl->reflow()
+
+  class VerticalReflow: public ReflowLayout:
+    public:
+    using ReflowLayout::pack_start;
+    using ReflowLayout::pack_end;
+    using ReflowLayout::pack_center;
+
+    VerticalReflow(int x, y, w, h, Scene s): ReflowLayout(x,y,w,h,s):
+      pass
+
+    void reflow():
+      debug "REFLOWING VERTICAL"
+      offset := 0
+      shared_ptr<Widget> w
+      for auto pw : self.start:
+        if pw.sp != NULL:
+          padding := pw.padding
+          pw.sp->y += offset + self.y + padding
+          pw.sp->x += self.x
+          offset += pw.sp->h + padding
+          pw.sp->on_reflow()
+        if pw.sl != NULL:
+          padding := pw.padding
+          pw.sl->y += offset + self.y + padding
+          pw.sl->x += self.x
+          offset += pw.sl->h + padding
+          pw.sl->reflow()
+
+      offset = self.h
+      for auto pw : self.end:
+        if pw.sp != NULL:
+          padding = pw.padding
+          pw.sp->y = self.y + offset - pw.sp->h - padding
+          pw.sp->x += self.x
+          offset -= pw.sp->h + padding
+          pw.sp->on_reflow()
+        if pw.sl != NULL:
+          padding = pw.padding
+          pw.sl->y = self.y + offset - pw.sl->h - padding
+          pw.sl->x += self.x
+          offset -= pw.sl->h + padding
+          pw.sl->reflow()
+
+      for auto pw : self.center:
+        if pw.sp != NULL:
+          leftover := self.h - pw.sp->h
+          padding_y := 0
+          if leftover > 0:
+            padding_y = leftover / 2
+          pw.sp->y = self.y + padding_y
+          pw.sp->x += self.x
+          pw.sp->on_reflow()
+        if pw.sl != NULL:
+          leftover := self.h - pw.sl->h
+          padding_y := 0
+          if leftover > 0:
+            padding_y = leftover / 2
+          pw.sl->y = self.y + padding_y
+          pw.sl->x += self.x
+          pw.sl->reflow()
+

src/rmkit/ui/ui.cpy

@@ -4,6 +4,7 @@
 #include "dialog.h"
 #include "dropdown.h"
 #include "layouts.h"
+#include "reflow.h"
 #include "main_loop.h"
 #include "pager.h"
 #include "pixmap.h"

src/rmkit/ui/widget.cpy

@@ -4,12 +4,38 @@
 #include "../util/signals.h"
 
 namespace ui:
+  class Rect:
+    public:
+    // variables: x, y, w, h
+    //
+    // x - the x coordinate of the widget.
+    // y - the y coordinate of the widget.
+    // w - the width of the widget
+    // h - the height of the widget
+    int x, y, w, h
+    int _x, _y, _w, _h // the original values the widget was instantiated with
+
+    Rect(int x,y,w,h): x(x), y(y), w(w), h(h), _x(x), _y(y), _w(w), _h(h):
+      pass
+
+    // this restores the coordinates of a widget to the coords it was initially
+    // given when it was constructed. this could be used to support reflowing
+    // widgets
+    void restore_coords():
+      x = _x
+      y = _y
+      w = _w
+      h = _h
+
+    virtual void on_reflow():
+      pass
+
   // Class: ui::Widget
   //
   // The widget class is the base of all other widgets. A widget is typically
   // a piece of UI that can receive inputs and draw to screen through the
   // frame buffer
-  class Widget:
+  class Widget : public Rect:
     public:
 
     // variable: fb
@@ -22,14 +48,6 @@ namespace ui:
     GESTURE_EVENTS_DELEGATE gestures = { &mouse }
     KEY_EVENTS kbd
 
-    // variables: x, y, w, h
-    //
-    // x - the x coordinate of the widget.
-    // y - the y coordinate of the widget.
-    // w - the width of the widget
-    // h - the height of the widget
-    int x, y, w, h
-    int _x, _y, _w, _h // the original values the widget was instantiated with
     int mouse_down = false, mouse_inside = false, mouse_down_first = false, mouse_x, mouse_y
     int dirty = 1
     bool visible = true
@@ -43,7 +61,7 @@ namespace ui:
     // y - the y coord of the top left of the widget
     // w - the width of the widget
     // h - the height of the widget
-    Widget(int x,y,w,h): x(x), y(y), w(w), h(h), _x(x), _y(y), _w(w), _h(h):
+    Widget(int x,y,w,h): Rect(x,y,w,h):
       self.install_signal_handlers()
 
     virtual ~Widget():
@@ -192,15 +210,6 @@ namespace ui:
       if d != -1:
         self.h = d
 
-    // this restores the coordinates of a widget to the coords it was initially
-    // given when it was constructed. this could be used to support reflowing
-    // widgets
-    void restore_coords():
-      x = _x
-      y = _y
-      w = _w
-      h = _h
-
     // function: get_render_size
     // gets the size of the rendered widget. this is for variable sized widgets
     // like text widgets which might have different sizes depending on the