improve image loading a bit (close #6)

components/chatmessage.cpp

@@ -1,6 +1,7 @@
 #include "chatmessage.hpp"
 #include "../abaddon.hpp"
 #include "../util.hpp"
+#include "lazyimage.hpp"
 #include <unordered_map>
 
 constexpr const int EmojiSize = 24; // settings eventually
@@ -116,35 +117,11 @@ void ChatMessageItemContainer::UpdateContent() {
 
     if (data->Embeds.size() == 1) {
         m_embed_component = CreateEmbedComponent(data->Embeds[0]);
-        if (m_embed_imgurl.size() > 0) {
-            m_signal_image_load.emit(m_embed_imgurl);
-        }
         AttachEventHandlers(*m_embed_component);
         m_main->add(*m_embed_component);
     }
 }
 
-void ChatMessageItemContainer::UpdateImage(std::string url, Glib::RefPtr<Gdk::Pixbuf> buf) {
-    if (!buf) return;
-
-    if (m_embed_img != nullptr && m_embed_imgurl == url) {
-        int w, h;
-        m_embed_img->get_size_request(w, h);
-        m_embed_img->property_pixbuf() = buf->scale_simple(w, h, Gdk::INTERP_BILINEAR);
-
-        return;
-    }
-
-    auto it = m_img_loadmap.find(url);
-    if (it != m_img_loadmap.end()) {
-        const auto inw = it->second.second.first;
-        const auto inh = it->second.second.second;
-        int w, h;
-        GetImageDimensions(inw, inh, w, h);
-        it->second.first->property_pixbuf() = buf->scale_simple(w, h, Gdk::INTERP_BILINEAR);
-    }
-}
-
 void ChatMessageItemContainer::UpdateReactions() {
     if (m_reactions_component != nullptr)
         delete m_reactions_component;
@@ -179,11 +156,6 @@ void ChatMessageItemContainer::UpdateAttributes() {
         m_attrib_label->set_markup("<span color='#999999'>[edited]</span>");
 }
 
-bool ChatMessageItemContainer::EmitImageLoad(std::string url) {
-    m_signal_image_load.emit(url);
-    return false;
-}
-
 void ChatMessageItemContainer::AddClickHandler(Gtk::Widget *widget, std::string url) {
     // clang-format off
     widget->signal_button_press_event().connect([url](GdkEventButton *event) -> bool {
@@ -351,24 +323,23 @@ Gtk::Widget *ChatMessageItemContainer::CreateEmbedComponent(const EmbedData &emb
     bool is_img = embed.Image.has_value() && embed.Image->ProxyURL.has_value();
     bool is_thumb = embed.Thumbnail.has_value() && embed.Thumbnail->ProxyURL.has_value();
     if (is_img || is_thumb) {
-        auto *img = Gtk::manage(new Gtk::Image);
-        img->set_halign(Gtk::ALIGN_CENTER);
-        img->set_margin_top(5);
         int w = 0, h = 0;
         if (is_img)
             GetImageDimensions(*embed.Image->Width, *embed.Image->Height, w, h, EmbedImageWidth, EmbedImageHeight);
         else
             GetImageDimensions(*embed.Thumbnail->Width, *embed.Thumbnail->Height, w, h, EmbedImageWidth, EmbedImageHeight);
+
+        std::string url;
+        if (is_img)
+            url = *embed.Image->ProxyURL;
+        else
+            url = *embed.Thumbnail->ProxyURL;
+
+        auto *img = Gtk::manage(new LazyImage(url, w, h, false));
+        img->set_halign(Gtk::ALIGN_CENTER);
+        img->set_margin_top(5);
         img->set_size_request(w, h);
         main->pack_start(*img);
-        m_embed_img = img;
-        if (is_img)
-            m_embed_imgurl = *embed.Image->ProxyURL;
-        else
-            m_embed_imgurl = *embed.Thumbnail->ProxyURL;
-
-        Abaddon::Get().GetImageManager().LoadFromURL(m_embed_imgurl,
-                                                     sigc::mem_fun(*this, &ChatMessageItemContainer::OnEmbedImageLoad));
     }
 
     if (embed.Footer.has_value()) {
@@ -410,14 +381,13 @@ Gtk::Widget *ChatMessageItemContainer::CreateImageComponent(const std::string &p
     GetImageDimensions(inw, inh, w, h);
 
     Gtk::EventBox *ev = Gtk::manage(new Gtk::EventBox);
-    Gtk::Image *widget = Gtk::manage(new Gtk::Image);
+    Gtk::Image *widget = Gtk::manage(new LazyImage(proxy_url, w, h, false));
     ev->add(*widget);
     widget->set_halign(Gtk::ALIGN_START);
     widget->set_size_request(w, h);
 
     AttachEventHandlers(*ev);
     AddClickHandler(ev, url);
-    HandleImage(w, h, *widget, proxy_url);
 
     return ev;
 }
@@ -608,18 +578,6 @@ void ChatMessageItemContainer::ReactionUpdateImage(Gtk::Image *img, const Glib::
     img->property_pixbuf() = pb->scale_simple(16, 16, Gdk::INTERP_BILINEAR);
 }
 
-void ChatMessageItemContainer::HandleImage(int w, int h, Gtk::Image &img, std::string url) {
-    m_img_loadmap[url] = { &img, { w, h } };
-    // ask the chatwindow to call UpdateImage because dealing with lifetimes sucks
-    Glib::signal_idle().connect(sigc::bind(sigc::mem_fun(*this, &ChatMessageItemContainer::EmitImageLoad), url));
-}
-
-void ChatMessageItemContainer::OnEmbedImageLoad(const Glib::RefPtr<Gdk::Pixbuf> &pixbuf) {
-    int w, h;
-    m_embed_img->get_size_request(w, h);
-    m_embed_img->property_pixbuf() = pixbuf->scale_simple(w, h, Gdk::INTERP_BILINEAR);
-}
-
 Glib::ustring ChatMessageItemContainer::GetText(const Glib::RefPtr<Gtk::TextBuffer> &buf) {
     Gtk::TextBuffer::iterator a, b;
     buf->get_bounds(a, b);
@@ -986,10 +944,6 @@ ChatMessageItemContainer::type_signal_action_reaction_remove ChatMessageItemCont
     return m_signal_action_reaction_remove;
 }
 
-ChatMessageItemContainer::type_signal_image_load ChatMessageItemContainer::signal_image_load() {
-    return m_signal_image_load;
-}
-
 void ChatMessageItemContainer::AttachEventHandlers(Gtk::Widget &widget) {
     const auto on_button_press_event = [this](GdkEventButton *event) -> bool {
         if (event->type == GDK_BUTTON_PRESS && event->button == GDK_BUTTON_SECONDARY) {

components/chatmessage.hpp

@@ -13,12 +13,9 @@ public:
     // attributes = edited, deleted
     void UpdateAttributes();
     void UpdateContent();
-    void UpdateImage(std::string url, Glib::RefPtr<Gdk::Pixbuf> buf);
     void UpdateReactions();
 
 protected:
-    bool EmitImageLoad(std::string url);
-
     void AddClickHandler(Gtk::Widget *widget, std::string);
     Gtk::TextView *CreateTextComponent(const Message *data); // Message.Content
     void UpdateTextComponent(Gtk::TextView *tv);
@@ -29,9 +26,6 @@ protected:
     Gtk::Widget *CreateReactionsComponent(const Message &data);
     Gtk::Widget *CreateReplyComponent(const Message &data);
     void ReactionUpdateImage(Gtk::Image *img, const Glib::RefPtr<Gdk::Pixbuf> &pb);
-    void HandleImage(int w, int h, Gtk::Image &img, std::string url);
-
-    void OnEmbedImageLoad(const Glib::RefPtr<Gdk::Pixbuf> &pixbuf);
 
     static Glib::ustring GetText(const Glib::RefPtr<Gtk::TextBuffer> &buf);
 
@@ -59,8 +53,6 @@ protected:
     std::map<Glib::RefPtr<Gtk::TextTag>, std::string> m_link_tagmap;
     std::map<Glib::RefPtr<Gtk::TextTag>, Snowflake> m_channel_tagmap;
 
-    std::unordered_map<std::string, std::pair<Gtk::Image *, std::pair<int, int>>> m_img_loadmap; // url -> [img, [w, h]]
-
     void AttachEventHandlers(Gtk::Widget &widget);
     void ShowMenu(GdkEvent *event);
 
@@ -78,16 +70,12 @@ protected:
     Gtk::EventBox *m_ev;
     Gtk::Box *m_main;
     Gtk::Label *m_attrib_label = nullptr;
-    Gtk::Image *m_embed_img = nullptr; // yes this is hacky no i dont care (for now)
-    std::string m_embed_imgurl;
 
     Gtk::TextView *m_text_component = nullptr;
     Gtk::Widget *m_embed_component = nullptr;
     Gtk::Widget *m_reactions_component = nullptr;
 
 public:
-    typedef sigc::signal<void, std::string> type_signal_image_load;
-
     typedef sigc::signal<void> type_signal_action_delete;
     typedef sigc::signal<void> type_signal_action_edit;
     typedef sigc::signal<void, Snowflake> type_signal_channel_click;
@@ -101,17 +89,12 @@ public:
     type_signal_channel_click signal_action_channel_click();
     type_signal_action_reaction_add signal_action_reaction_add();
     type_signal_action_reaction_remove signal_action_reaction_remove();
-
-    type_signal_image_load signal_image_load();
-
 private:
     type_signal_action_delete m_signal_action_delete;
     type_signal_action_edit m_signal_action_edit;
     type_signal_channel_click m_signal_action_channel_click;
     type_signal_action_reaction_add m_signal_action_reaction_add;
     type_signal_action_reaction_remove m_signal_action_reaction_remove;
-
-    type_signal_image_load m_signal_image_load;
 };
 
 class ChatMessageHeader : public Gtk::ListBoxRow {

components/chatwindow.cpp

@@ -250,16 +250,6 @@ void ChatWindow::ProcessNewMessage(Snowflake id, bool prepend) {
         content->signal_action_reaction_remove().connect([this, id](const Glib::ustring &param) {
             m_signal_action_reaction_remove.emit(id, param);
         });
-        content->signal_image_load().connect([this, id](std::string url) {
-            auto &mgr = Abaddon::Get().GetImageManager();
-            mgr.LoadFromURL(url, [this, id, url](Glib::RefPtr<Gdk::Pixbuf> buf) {
-                if (m_id_to_widget.find(id) != m_id_to_widget.end()) {
-                    auto *x = dynamic_cast<ChatMessageItemContainer *>(m_id_to_widget.at(id));
-                    if (x != nullptr)
-                        x->UpdateImage(url, buf);
-                }
-            });
-        });
         content->signal_action_channel_click().connect([this](const Snowflake &id) {
             m_signal_action_channel_click.emit(id);
         });

components/lazyimage.cpp

@@ -0,0 +1,41 @@
+#include "lazyimage.hpp"
+#include "../abaddon.hpp"
+
+LazyImage::LazyImage(int w, int h, bool use_placeholder)
+    : m_width(w)
+    , m_height(h) {
+    static int sidx = 0;
+    sidx++;
+    m_idx = sidx;
+    if (use_placeholder)
+        property_pixbuf() = Abaddon::Get().GetImageManager().GetPlaceholder(w)->scale_simple(w, h, Gdk::INTERP_BILINEAR);
+    signal_draw().connect(sigc::mem_fun(*this, &LazyImage::OnDraw));
+}
+
+LazyImage::LazyImage(const std::string &url, int w, int h, bool use_placeholder)
+    : m_url(url)
+    , m_width(w)
+    , m_height(h) {
+    static int sidx = 0;
+    sidx++;
+    m_idx = sidx;
+    if (use_placeholder)
+        property_pixbuf() = Abaddon::Get().GetImageManager().GetPlaceholder(w)->scale_simple(w, h, Gdk::INTERP_BILINEAR);
+    signal_draw().connect(sigc::mem_fun(*this, &LazyImage::OnDraw));
+}
+
+void LazyImage::SetURL(const std::string &url) {
+    m_url = url;
+}
+
+bool LazyImage::OnDraw(const Cairo::RefPtr<Cairo::Context> &context) {
+    if (!m_needs_request || m_url == "") return false;
+    m_needs_request = false;
+
+    auto cb = [this](const Glib::RefPtr<Gdk::Pixbuf> &pb) {
+        property_pixbuf() = pb->scale_simple(m_width, m_height, Gdk::INTERP_BILINEAR);
+    };
+    Abaddon::Get().GetImageManager().LoadFromURL(m_url, sigc::track_obj(cb, *this));
+
+    return false;
+}

components/lazyimage.hpp

@@ -0,0 +1,20 @@
+#pragma once
+#include <gtkmm.h>
+
+// loads an image only when the widget is drawn for the first time
+class LazyImage : public Gtk::Image {
+public:
+    LazyImage(int w, int h, bool use_placeholder = true);
+    LazyImage(const std::string &url, int w, int h, bool use_placeholder = true);
+
+    void SetURL(const std::string &url);
+
+private:
+    bool OnDraw(const Cairo::RefPtr<Cairo::Context> &context);
+
+    bool m_needs_request = true;
+    int m_idx;
+    std::string m_url;
+    int m_width;
+    int m_height;
+};

components/memberlist.cpp

@@ -7,7 +7,10 @@ MemberListUserRow::MemberListUserRow(Snowflake guild_id, const UserData *data) {
     m_ev = Gtk::manage(new Gtk::EventBox);
     m_box = Gtk::manage(new Gtk::Box(Gtk::ORIENTATION_HORIZONTAL));
     m_label = Gtk::manage(new Gtk::Label);
-    m_avatar = Gtk::manage(new Gtk::Image(Abaddon::Get().GetImageManager().GetPlaceholder(16)));
+    m_avatar = Gtk::manage(new LazyImage(16, 16));
+
+    if (data->HasAvatar())
+        m_avatar->SetURL(data->GetAvatarURL("png"));
 
     get_style_context()->add_class("members-row");
     get_style_context()->add_class("members-row-member");
@@ -142,22 +145,6 @@ void MemberList::UpdateMemberListInternal() {
     auto add_user = [this, &user_to_color](const UserData *data) {
         auto *row = Gtk::manage(new MemberListUserRow(m_guild_id, data));
         m_id_to_row[data->ID] = row;
-
-        if (data->HasAvatar()) {
-            Snowflake id = data->ID;
-            Abaddon::Get().GetImageManager().LoadFromURL(data->GetAvatarURL("png", "16"), [this, id](Glib::RefPtr<Gdk::Pixbuf> pbuf) {
-                Glib::signal_idle().connect([this, id, pbuf]() -> bool {
-                    if (m_id_to_row.find(id) != m_id_to_row.end()) {
-                        auto *foundrow = static_cast<MemberListUserRow *>(m_id_to_row.at(id));
-                        if (foundrow != nullptr)
-                            foundrow->SetAvatarFromPixbuf(pbuf);
-                    }
-
-                    return false;
-                });
-            });
-        }
-
         AttachUserMenuHandler(row, data->ID);
         m_listbox->add(*row);
     };

components/memberlist.hpp

@@ -3,6 +3,7 @@
 #include <mutex>
 #include <unordered_map>
 #include "../discord/discord.hpp"
+#include "lazyimage.hpp"
 
 class MemberListUserRow : public Gtk::ListBoxRow {
 public:
@@ -14,7 +15,7 @@ public:
 private:
     Gtk::EventBox *m_ev;
     Gtk::Box *m_box;
-    Gtk::Image *m_avatar;
+    LazyImage *m_avatar;
     Gtk::Label *m_label;
 };