add a way to pre-render svgs to fix duplication of surfaces

meson.build

@@ -5,7 +5,7 @@ project(
 )
 project_description = 'The Raven user interface library'
 
-add_project_arguments('-g3',  language : 'cpp')
+add_project_arguments('-O3', language : 'cpp')
 
 cairomm_dep = dependency('cairomm-1.0')
 pangocairo_dep = dependency('pangocairo')
@@ -22,6 +22,7 @@ raven_dependencies = [
 headers = include_directories('src')
 
 raven_source_files = [
+  './src/SvgUtil.cpp',
   './src/Box.cpp',
   './src/Styles.cpp',
   './src/Painter.cpp',
@@ -38,6 +39,7 @@ raven_source_files = [
 ]
 
 raven_header_files = [
+  './src/SvgUtil.hpp',
   './src/Logging.hpp',
   './src/Box.hpp',
   './src/BoxLayout.hpp',

src/SvgUtil.cpp

@@ -0,0 +1,35 @@
+#include "SvgUtil.hpp"
+#include "librsvg/rsvg.h"
+#include <iostream>
+#include "cairomm/context.h"
+
+namespace Raven {
+
+Cairo::RefPtr<Cairo::ImageSurface> render_svg(std::string path, double x, double y, double width, double height) {
+    auto file = g_file_new_for_path(path.c_str());
+    auto handle = rsvg_handle_new_from_gfile_sync(file, RSVG_HANDLE_FLAGS_NONE, NULL, NULL);
+
+    if (!handle) {
+        std::cerr << "could not load svg file: " << path << std::endl;
+        exit(EXIT_FAILURE);
+    }
+
+    RsvgRectangle viewport = {
+        .x = x,
+        .y = y,
+        .width = width,
+        .height = height,
+    };
+
+    auto surface = Cairo::ImageSurface::create(Cairo::Format::FORMAT_ARGB32, width, height);
+    auto context = Cairo::Context::create(surface);
+
+    rsvg_handle_render_document(handle, context->cobj(), &viewport, NULL);
+
+    g_object_unref(file);
+    g_object_unref(handle);
+
+    return surface;
+}
+
+}

src/SvgUtil.hpp

@@ -0,0 +1,10 @@
+#pragma once
+
+#include "cairomm/refptr.h"
+#include "cairomm/surface.h"
+
+namespace Raven {
+
+Cairo::RefPtr<Cairo::ImageSurface> render_svg(std::string path, double x, double y, double width, double height);
+
+}

src/SvgWidget.cpp

@@ -6,11 +6,16 @@
 namespace Raven {
 
 void SvgWidget::on_init() {
+    set_style(&clear_widget_style);
+
+    if (m_user_defined_surface) {
+        set_did_init(true);
+        return;
+    }
+
     m_file = g_file_new_for_path(m_path.c_str());
     m_handle = rsvg_handle_new_from_gfile_sync(m_file, RSVG_HANDLE_FLAGS_NONE, NULL, NULL);
 
-    set_style(&clear_widget_style);
-
     if (!m_handle) {
         std::cerr << "could not load svg file: " << m_path << std::endl;
         exit(EXIT_FAILURE);
@@ -20,6 +25,10 @@ void SvgWidget::on_init() {
 }
 
 void SvgWidget::on_after_layout() {
+    if (m_user_defined_surface) {
+        return;
+    }
+
     auto width = rect().width();
     auto height = rect().height();
 
@@ -52,8 +61,10 @@ void SvgWidget::on_paint() {
 }
 
 SvgWidget::~SvgWidget() {
-    g_object_unref(m_file);
+    if (m_file)
-    g_object_unref(m_handle);
+        g_object_unref(m_file);
+    if (m_handle)
+        g_object_unref(m_handle);
 }
 
 }

src/SvgWidget.hpp

@@ -16,6 +16,11 @@ public:
         : Raven::Widget()
         , m_path(path) {}
 
+    SvgWidget(Cairo::RefPtr<Cairo::ImageSurface> image_surface)
+        : Raven::Widget()
+        , m_image_surface(image_surface)
+        , m_user_defined_surface(true) {}
+
     ~SvgWidget();
 
     std::string &path() { return m_path; }
@@ -26,12 +31,13 @@ protected:
     void on_paint();
 private:
     std::string m_path;
-    RsvgHandle *m_handle;
+    RsvgHandle *m_handle { nullptr };
-    GFile *m_file;
+    GFile *m_file { nullptr };
-    Cairo::RefPtr<Cairo::Context> m_image_context;
+    Cairo::RefPtr<Cairo::Context> m_image_context { nullptr };
-    Cairo::RefPtr<Cairo::ImageSurface> m_image_surface;
+    Cairo::RefPtr<Cairo::ImageSurface> m_image_surface { nullptr };
     double m_known_width { 0.0 };
     double m_known_height { 0.0 };
+    bool m_user_defined_surface { false };
 };
 
 }

src/Widget.cpp

@@ -115,6 +115,7 @@ void Widget::remove_child(std::shared_ptr<Widget> child) {
 
 void Widget::clear_children() {
     m_children.clear();
+    m_children.shrink_to_fit();
     reflow();
 }
 

src/main.cpp

@@ -29,24 +29,22 @@ int main() {
     top_bar->set_layout<Raven::BoxLayout>(Raven::Direction::Horizontal);
 
     auto container_widget = main_widget->add<Raven::Widget>();
-    auto container_layout = container_widget->set_layout<Raven::BoxLayout>(Raven::Direction::Vertical);
+    container_widget->set_layout<Raven::DocumentLayout>();
-    container_layout->set_spacing(5);
-    container_layout->set_margin(18);
-    container_widget->resize(400, 400);
 
     auto new_button = top_bar->add<Raven::Button>("add");
     new_button->rect().set_max_width(50);
-    new_button->on_click = [container_widget]() {
+    new_button->on_click = [&window, container_widget]() {
-        container_widget->add<Raven::Button>("hello");
+        window.queue_microtask([container_widget]() {
+            for (int i = 0; i < 5000; i++) {
+                container_widget->add<Raven::Button>("hello");
+            }
+        });
     };
+
     auto remove_button = top_bar->add<Raven::Button>("remove");
     remove_button->on_click = [container_widget]() {
-        if (container_widget->children().size() > 0) {
+        container_widget->clear_children();
-            container_widget->remove_child(container_widget->children()[0]);
-        }
     };
-    auto dummy_button = top_bar->add<Raven::Button>("dummy");
-    dummy_button->rect().set_max_width(60);
 
     window.run(true);
     return 0;