adapted to new update/render interface; added fading-rects module

Makefile

@@ -1,5 +1,5 @@
 BIN := $(shell basename $$(pwd))
-PLUGINS := rects skembo huey
+PLUGINS := rects skembo huey fading-rects
 
 MAKE += --no-print-directory
 

fading-rects/FadingRects.cpp

@@ -0,0 +1,143 @@
+//
+// FadingRects.cpp
+// screensaver
+//
+// Created by Bob Polis at 2020-10-26
+// Copyright (c) 2020 SwiftCoder. All rights reserved.
+//
+
+#include "FadingRects.hpp"
+#include <libscscreensaver.hpp>
+#include <string>
+#include <sstream>
+#include <iomanip>
+#include <vector>
+#include <algorithm>
+#include <random>
+
+const int default_frames_per_rect {10};
+
+enum class FadingState {
+    fadein,
+    sustain,
+    fadeout
+};
+
+struct Rect {
+    double x {0};
+    double y {0};
+    double width {0};
+    double height {0};
+    double red {0.0};
+    double green {0.0};
+    double blue {0.0};
+    double alpha {1.0};
+    double cur_alpha {0.0};
+    double delta {0.0};
+    FadingState state {FadingState::fadein};
+    int sustain_frame {0};
+    double line_width {2.0};
+};
+
+
+class FadingRects : public ScreensaverPlugin {
+    public:
+        FadingRects() = default;
+        ~FadingRects() = default;
+
+        int fps() const override;
+        void update () override;
+        void render() override;
+
+    private:
+        double _hue {0.0};
+        std::vector<Rect> _rects;
+        int _frames_per_rect {default_frames_per_rect};
+        std::uniform_real_distribution<double> _random_line_width {1.0, 20.0};
+
+        Color next_color();
+};
+
+ScreensaverPlugin* create_instance() {
+    return new FadingRects;
+}
+
+int FadingRects::fps() const {
+    return 30;
+}
+
+void FadingRects::update() {
+    // adjust rects
+    for (Rect& r : _rects) {
+        switch (r.state) {
+            case FadingState::fadein:
+                r.cur_alpha += r.delta;
+                if (r.cur_alpha > r.alpha) {
+                    r.cur_alpha = r.alpha;
+                    r.state = FadingState::sustain;
+                }
+                break;
+            case FadingState::sustain:
+                r.sustain_frame++;
+                if (r.sustain_frame > fps()) {
+                    r.state = FadingState::fadeout;
+                }
+                break;
+            case FadingState::fadeout:
+                r.cur_alpha -= r.delta;
+                break;
+        }
+    }
+    auto it = std::remove_if(_rects.begin(), _rects.end(), [](const Rect& r) {
+        return r.cur_alpha < 0.0;
+    });
+    _rects.erase(it, _rects.end());
+
+    // add new rect, if allowed
+    _frames_per_rect--;
+    if (_frames_per_rect == 0) {
+        _frames_per_rect = default_frames_per_rect;
+        cairo_rectangle_t rr {random_rect()};
+        RGB rgb {RGB(next_color())};
+        Rect rect;
+        rect.red = rgb.r;
+        rect.green = rgb.g;
+        rect.blue = rgb.b;
+        rect.alpha = random01();
+        rect.cur_alpha = 0.0;
+        rect.state = FadingState::fadein;
+        rect.sustain_frame = 0;
+        rect.delta = rect.alpha / (5 * fps());
+        rect.line_width = _random_line_width(_eng);
+        rect.x = rr.x;
+        rect.y = rr.y;
+        rect.width = rr.width;
+        rect.height = rr.height;
+        _rects.push_back(rect);
+    }
+}
+
+void FadingRects::render() {
+    // clear screen
+    make_black();
+
+    // render rects
+    for (Rect r : _rects) {
+        cairo_set_source_rgba(_c, r.red, r.green, r.blue, r.cur_alpha);
+        cairo_rectangle(_c, r.x, r.y, r.width, r.height);
+        cairo_set_line_width(_c, r.line_width);
+        cairo_stroke(_c);
+    }
+}
+
+Color FadingRects::next_color() {
+    _hue += 0.5;
+    if (_hue >= 360.0) {
+        _hue -= 360.0;
+    }
+    HSB hsb;
+    hsb.h = _hue;
+    hsb.s = random01();
+    hsb.b = random01();
+    return Color {hsb};
+}

fading-rects/FadingRects.hpp

@@ -0,0 +1,18 @@
+//
+// FadingRects.hpp
+// screensaver
+//
+// Created by Bob Polis at 2020-10-26
+// Copyright (c) 2020 SwiftCoder. All rights reserved.
+//
+
+#ifndef _Huey_H_
+#define _Huey_H_
+
+class ScreensaverPlugin;
+
+extern "C" {
+    ScreensaverPlugin* create_instance();
+}
+
+#endif // _Huey_H_

fading-rects/Makefile

@@ -0,0 +1,62 @@
+LIBNAME := $(shell basename $$(pwd))
+MAJOR := 1
+MINOR := 0.0
+
+UNAME_S := $(shell uname -s)
+
+ifeq ($(UNAME_S),Darwin)
+	LINKERNAME := $(LIBNAME).dylib
+	SONAME := $(LIBNAME).$(MAJOR).dylib
+	REALNAME := $(LINKERNAME)
+else
+	LINKERNAME := $(LIBNAME).so
+	SONAME := $(LINKERNAME).$(MAJOR)
+	REALNAME := $(SONAME).$(MINOR)
+endif
+
+PREFIX ?= ..
+LIBDIR ?= $(PREFIX)/plugins
+
+SRCS := $(wildcard *.cpp)
+OBJS := $(subst .cpp,.o,$(SRCS))
+DEPS := $(subst .cpp,.d,$(SRCS))
+HDRS := $(filter-out $(LIBNAME).hpp,$(wildcard *.hpp))
+
+CXX ?= g++
+
+CXXFLAGS := $(CXXFLAGS) -Wshadow -Wall -Wpedantic -Wextra -g -fno-strict-aliasing -std=c++17 -fPIC
+ifeq ($(DEBUG),1)
+	CXXFLAGS += -D DEBUG -O0
+else
+	CXXFLAGS += -D NDEBUG -O3
+endif
+
+LDLIBS := -lcairo -lscscreensaver
+
+RM := /bin/rm -f
+INSTALL := /usr/bin/install -c
+
+.PHONY: all clean install
+
+all: $(REALNAME)
+
+$(REALNAME): $(OBJS) $(DEPS)
+ifeq ($(UNAME_S),Darwin)
+	$(CXX) -dynamiclib -o $(REALNAME) -current_version $(MAJOR) -compatibility_version $(MINOR) $(LDFLAGS) $(LDLIBS) $(OBJS)
+else
+	$(CXX) -g -shared -Wl,-soname,$(SONAME) -o $(REALNAME) $(LDFLAGS) $(LDLIBS) $(OBJS)
+endif
+
+%.o: %.cpp %.d Makefile
+	$(CXX) $(CXXFLAGS) -MMD -MP -MT $@ -MF $*.d -c $<
+
+-include *.d
+
+%.d: ;
+
+clean:
+	$(RM) $(OBJS) $(DEPS) $(REALNAME)
+
+install: $(REALNAME)
+	$(INSTALL) -d $(LIBDIR)
+	$(INSTALL) -m 644 $(REALNAME) $(LIBDIR)/$(LIBNAME).saver

huey/Huey.cpp

@@ -18,7 +18,8 @@ class Huey : public ScreensaverPlugin {
         ~Huey() = default;
 
         int fps() const override;
-        void draw_frame() override;
+        void update() override;
+        void render() override;
 
     private:
         double _hue {0};
@@ -32,7 +33,11 @@ int Huey::fps() const {
     return 5;
 }
 
-void Huey::draw_frame() {
+void Huey::update() {
+
+}
+
+void Huey::render() {
     // next color
     HSB hsb;
     hsb.h = _hue;

main.cpp

@@ -52,8 +52,9 @@ void list_plugins() {
 }
 
 void draw() {
+    main_saver->update();
     sc::gui::ImageLock lock {*main_image};
-    main_saver->draw_frame();
+    main_saver->render();
     main_window->dirty(true);
     main_window->show_image(*main_image);
 }

rects/RectSaver.cpp

@@ -15,7 +15,8 @@ class RectSaver : public ScreensaverPlugin {
         ~RectSaver() = default;
 
         int fps() const override;
-        void draw_frame() override;
+        void update() override;
+        void render() override;
 };
 
 ScreensaverPlugin* create_instance() {
@@ -26,7 +27,11 @@ int RectSaver::fps() const {
     return 2;
 }
 
-void RectSaver::draw_frame() {
+void RectSaver::update() {
+
+}
+
+void RectSaver::render() {
     cairo_set_source_rgb(_c, random01(), random01(), random01());
     cairo_rectangle_t rect {random_rect()};
     cairo_rectangle(_c, rect.x, rect.y, rect.width, rect.height);

skembo/Skembo.cpp

@@ -15,7 +15,8 @@ class Skembo : public ScreensaverPlugin {
         ~Skembo() = default;
 
         int fps() const override;
-        void draw_frame() override;
+        void update() override;
+        void render() override;
 
     private:
         double _hue {0};
@@ -29,7 +30,11 @@ int Skembo::fps() const {
     return 40;
 }
 
-void Skembo::draw_frame() {
+void Skembo::update() {
+
+}
+
+void Skembo::render() {
     // next color
     HSB hsb;
     hsb.h = _hue;