FontEditor: Inherit GlyphMapWidget from ScrollableWidget

This makes it easier to work in FontEditor at low resolution.
Previously glyph map resized itself and the parent window to
accomodate fonts, which isn't ideal. Users typically control
window size/position after launch; widgets have to make do.

Userland/Applications/FontEditor/GlyphMapWidget.cpp

@@ -29,26 +29,36 @@
 #include <LibGfx/BitmapFont.h>
 #include <LibGfx/Palette.h>
 
-GlyphMapWidget::GlyphMapWidget(Gfx::BitmapFont& mutable_font)
+GlyphMapWidget::GlyphMapWidget()
-    : m_font(mutable_font)
 {
-    m_glyph_count = mutable_font.glyph_count();
-    set_relative_rect({ 0, 0, preferred_width(), preferred_height() });
     set_focus_policy(GUI::FocusPolicy::StrongFocus);
+    horizontal_scrollbar().set_visible(false);
 }
 
 GlyphMapWidget::~GlyphMapWidget()
 {
 }
 
-int GlyphMapWidget::preferred_width() const
+void GlyphMapWidget::initialize(Gfx::BitmapFont& mutable_font)
 {
-    return columns() * (font().max_glyph_width() + m_horizontal_spacing) + 2 + frame_thickness() * 2;
+    if (m_font == mutable_font)
+        return;
+    m_font = mutable_font;
+    m_glyph_count = mutable_font.glyph_count();
+    vertical_scrollbar().set_step(font().glyph_height() + m_vertical_spacing);
 }
 
-int GlyphMapWidget::preferred_height() const
+void GlyphMapWidget::resize_event(GUI::ResizeEvent& event)
 {
-    return rows() * (font().glyph_height() + m_vertical_spacing) + 2 + frame_thickness() * 2;
+    int event_width = event.size().width() - this->vertical_scrollbar().width() - (frame_thickness() * 2) - m_horizontal_spacing;
+    m_columns = max(event_width / (font().max_glyph_width() + m_horizontal_spacing), 1);
+    m_rows = ceil_div(m_glyph_count, m_columns);
+
+    int content_width = columns() * (font().max_glyph_width() + m_horizontal_spacing);
+    int content_height = rows() * (font().glyph_height() + m_vertical_spacing) + frame_thickness();
+    set_content_size({ content_width, content_height });
+
+    ScrollableWidget::resize_event(event);
 }
 
 void GlyphMapWidget::set_selected_glyph(int glyph)
@@ -71,7 +81,7 @@ Gfx::IntRect GlyphMapWidget::get_outer_rect(int glyph) const
         font().max_glyph_width() + m_horizontal_spacing,
         font().glyph_height() + m_horizontal_spacing
     }
-        .translated(frame_thickness(), frame_thickness());
+        .translated(frame_thickness() - horizontal_scrollbar().value(), frame_thickness() - vertical_scrollbar().value());
 }
 
 void GlyphMapWidget::update_glyph(int glyph)
@@ -84,10 +94,11 @@ void GlyphMapWidget::paint_event(GUI::PaintEvent& event)
     GUI::Frame::paint_event(event);
 
     GUI::Painter painter(*this);
+    painter.add_clip_rect(widget_inner_rect());
     painter.add_clip_rect(event.rect());
 
     painter.set_font(font());
-    painter.fill_rect(frame_inner_rect(), palette().base());
+    painter.fill_rect(widget_inner_rect(), palette().base());
 
     for (int glyph = 0; glyph < m_glyph_count; ++glyph) {
         Gfx::IntRect outer_rect = get_outer_rect(glyph);
@@ -125,33 +136,39 @@ void GlyphMapWidget::keydown_event(GUI::KeyEvent& event)
     if (event.key() == KeyCode::Key_Up) {
         if (selected_glyph() >= m_columns) {
             set_selected_glyph(selected_glyph() - m_columns);
+            scroll_to_glyph(selected_glyph());
             return;
         }
     }
     if (event.key() == KeyCode::Key_Down) {
         if (selected_glyph() < m_glyph_count - m_columns) {
             set_selected_glyph(selected_glyph() + m_columns);
+            scroll_to_glyph(selected_glyph());
             return;
         }
     }
     if (event.key() == KeyCode::Key_Left) {
         if (selected_glyph() > 0) {
             set_selected_glyph(selected_glyph() - 1);
+            scroll_to_glyph(selected_glyph());
             return;
         }
     }
     if (event.key() == KeyCode::Key_Right) {
         if (selected_glyph() < m_glyph_count - 1) {
             set_selected_glyph(selected_glyph() + 1);
+            scroll_to_glyph(selected_glyph());
             return;
         }
     }
     if (event.ctrl() && event.key() == KeyCode::Key_Home) {
         set_selected_glyph(0);
+        scroll_to_glyph(selected_glyph());
         return;
     }
     if (event.ctrl() && event.key() == KeyCode::Key_End) {
         set_selected_glyph(m_glyph_count - 1);
+        scroll_to_glyph(selected_glyph());
         return;
     }
     if (!event.ctrl() && event.key() == KeyCode::Key_Home) {
@@ -166,3 +183,16 @@ void GlyphMapWidget::keydown_event(GUI::KeyEvent& event)
         return;
     }
 }
+
+void GlyphMapWidget::scroll_to_glyph(int glyph)
+{
+    int row = glyph / columns();
+    int column = glyph % columns();
+    auto scroll_rect = Gfx::IntRect {
+        column * (font().max_glyph_width() + m_horizontal_spacing) + 1,
+        row * (font().glyph_height() + m_vertical_spacing) + 1,
+        font().max_glyph_width() + m_horizontal_spacing,
+        font().glyph_height() + m_horizontal_spacing
+    };
+    scroll_into_view(scroll_rect, true, true);
+}

Userland/Applications/FontEditor/GlyphMapWidget.h

@@ -26,25 +26,22 @@
 
 #pragma once
 
-#include <AK/Function.h>
+#include <LibGUI/ScrollableWidget.h>
-#include <AK/StdLibExtras.h>
-#include <LibGUI/Frame.h>
 #include <LibGfx/BitmapFont.h>
 
-class GlyphMapWidget final : public GUI::Frame {
+class GlyphMapWidget final : public GUI::ScrollableWidget {
     C_OBJECT(GlyphMapWidget)
 public:
     virtual ~GlyphMapWidget() override;
 
+    void initialize(Gfx::BitmapFont&);
+
     int selected_glyph() const { return m_selected_glyph; }
     void set_selected_glyph(int);
 
-    int rows() const { return ceil_div(m_glyph_count, m_columns); }
+    int rows() const { return m_rows; }
     int columns() const { return m_columns; }
 
-    int preferred_width() const;
-    int preferred_height() const;
-
     Gfx::BitmapFont& font() { return *m_font; }
     const Gfx::BitmapFont& font() const { return *m_font; }
 
@@ -53,16 +50,19 @@ public:
     Function<void(int)> on_glyph_selected;
 
 private:
-    explicit GlyphMapWidget(Gfx::BitmapFont&);
+    GlyphMapWidget();
     virtual void paint_event(GUI::PaintEvent&) override;
     virtual void mousedown_event(GUI::MouseEvent&) override;
     virtual void keydown_event(GUI::KeyEvent&) override;
+    virtual void resize_event(GUI::ResizeEvent&) override;
 
     Gfx::IntRect get_outer_rect(int glyph) const;
+    void scroll_to_glyph(int glyph);
 
     RefPtr<Gfx::BitmapFont> m_font;
-    int m_glyph_count;
+    int m_glyph_count { 384 };
     int m_columns { 32 };
+    int m_rows { 12 };
     int m_horizontal_spacing { 2 };
     int m_vertical_spacing { 2 };
     int m_selected_glyph { 0 };