add scrollbar, improve presets, other small fixes

src/node_scroll.cpp

@@ -2,6 +2,7 @@
 #include "log.h"
 #include "node_scroll.h"
 #include "event.h"
+#include "shader.h"
 
 NodeScroll::NodeScroll()
 {
@@ -25,6 +26,32 @@ void NodeScroll::fix_scroll()
     m_pos_offset_childred = m_offset;
 }
 
+void NodeScroll::handle_resize(glm::vec2 old_size, glm::vec2 new_size)
+{
+    Node::handle_resize(old_size, new_size);
+    fix_scroll();
+}
+
+void NodeScroll::draw()
+{
+    NodeBorder::draw();
+    glm::vec4 rect = get_children_rect();
+    if (rect.x == 0 || rect.w < m_size.y)
+        return;
+    float h = m_size.y / rect.w * m_size.y;
+    float offset_percent = m_offset.y / (rect.w - m_size.y);
+    float pr = YGNodeLayoutGetPadding(y_node, YGEdgeRight) - 5;
+    glDisable(GL_BLEND);
+    ShaderManager::use(kShader::Color);
+    ShaderManager::u_mat4(kShaderUniform::MVP, m_proj 
+        * glm::translate(glm::vec3(m_pos.x + m_size.x - pr, m_pos.y - offset_percent * (m_size.y - h), 0))
+        * glm::scale(glm::vec3(pr, h, 1)) 
+        * glm::translate(glm::vec3(.5, .5, 0))
+    );
+    ShaderManager::u_vec4(kShaderUniform::Col, { .3, .3, .3, 1 });
+    m_plane.draw_fill();
+}
+
 kEventResult NodeScroll::handle_event(Event* e)
 {
     NodeBorder::handle_event(e);
@@ -37,12 +64,14 @@ kEventResult NodeScroll::handle_event(Event* e)
         m_dragging = true;
         m_drag_start = me->m_pos;
         m_offset_start = m_offset;
+        // if click on the scroll area use scrolling direction, otherwise natural
+        m_scroll_dir = me->m_pos.x > (m_size.x - YGNodeLayoutGetPadding(y_node, YGEdgeRight) + 5) ? -1 : 1;
         mouse_capture();
         break;
     case kEventType::MouseMove:
         if (m_dragging)
         {
-            m_offset = m_offset_start + (me->m_pos - m_drag_start) * m_mask;
+            m_offset = m_offset_start + (me->m_pos - m_drag_start) * m_mask * m_scroll_dir;
             fix_scroll();
         }
         break;