Merge remote-tracking branch 'xdg-thumbnailer/xdg-thumbnailer'

.gitattributes

@@ -7,4 +7,5 @@ HexFiend/* linguist-vendored
 Core/*.h linguist-language=C
 SDL/*.h linguist-language=C
 Windows/*.h linguist-language=C
+XdgThumbnailer/*.h linguist-language=C
 Cocoa/*.h linguist-language=Objective-C

Core/gb.c

@@ -550,7 +550,7 @@ int GB_load_isx(GB_gameboy_t *gb, const char *path)
                 bank = byte;
                 if (byte >= 0x80) {
                     READ(byte);
-                    /* TODO: This is just a guess, the docs don't elaborator on how banks > 0xFF are saved,
+                    /* TODO: This is just a guess, the docs don't elaborate on how banks > 0xFF are saved,
                        other than the fact that banks >= 80 requires two bytes to store them, and I haven't
                        encountered an ISX file for a ROM larger than 4MBs yet. */
                     bank += byte << 7;

FreeDesktop/sameboy.xml

@@ -1,23 +1,38 @@
 <?xml version="1.0" encoding="utf-8"?>
 <mime-info xmlns='http://www.freedesktop.org/standards/shared-mime-info'>
-<mime-type type="application/x-gameboy-rom">
+  <mime-type type="application/x-gameboy-rom">
-  <comment>Game Boy ROM</comment>
+    <comment>Game Boy ROM</comment>
-  <icon name="x-gameboy-rom"/>
+    <icon name="x-gameboy-rom"/>
-  <glob-deleteall/>
+    <glob pattern="*.gb"/>
-  <glob pattern="*.gb"/>
+    <glob pattern="*.sgb"/>
-  <glob pattern="*.sgb"/>
+    <magic>
-</mime-type>
+      <!-- Nintendo logo starting at 0x0104. -->
-<mime-type type="application/x-gameboy-color-rom">
+      <match type="string" offset="260" value="\xCE\xED\x66\x66\xCC\x0D\x00\x0B\x03\x73\x00\x83\x00\x0C\x00\x0D\x00\x08\x11\x1F\x88\x89\x00\x0E\xDC\xCC\x6E\xE6\xDD\xDD\xD9\x99\xBB\xBB\x67\x63\x6E\x0E\xEC\xCC\xDD\xDC\x99\x9F\xBB\xB9\x33\x3E">
-  <comment>Game Boy Color ROM</comment>
+        <!-- 0x0143: bit 7 is set. -->
-  <icon name="x-gameboy-color-rom"/>
+        <match type="byte" offset="323" mask="128" value="0"/>
-  <glob-deleteall/>
+      </match>
-  <glob pattern="*.gbc"/>
+    </magic>
-  <glob pattern="*.cgb"/>
+  </mime-type>
-</mime-type>
+  <mime-type type="application/x-gameboy-color-rom">
-<mime-type type="application/x-gameboy-isx">
+    <comment>Game Boy Color ROM</comment>
-      <comment>Game Boy ISX binary</comment>
+    <icon name="x-gameboy-color-rom"/>
-      <icon name="x-gameboy-rom"/>
+    <glob pattern="*.gbc"/>
-      <glob-deleteall/>
+    <glob pattern="*.cgb"/>
-      <glob pattern="*.isx"/>
+    <magic>
-    </mime-type>
+      <!-- Nintendo logo starting at 0x0104. -->
+      <match type="string" offset="260" value="\xCE\xED\x66\x66\xCC\x0D\x00\x0B\x03\x73\x00\x83\x00\x0C\x00\x0D\x00\x08\x11\x1F\x88\x89\x00\x0E\xDC\xCC\x6E\xE6\xDD\xDD\xD9\x99\xBB\xBB\x67\x63\x6E\x0E\xEC\xCC\xDD\xDC\x99\x9F\xBB\xB9\x33\x3E">
+        <!-- 0x0143: bit 7 is set. -->
+        <match type="byte" offset="323" mask="128" value="128"/>
+      </match>
+    </magic>
+  </mime-type>
+  <mime-type type="application/x-gameboy-isx">
+    <comment>Game Boy ISX binary</comment>
+    <icon name="x-gameboy-rom"/>
+    <glob pattern="*.isx"/>
+    <!-- Only "extended" ISX files have this magic, but at least this will enable *some* detection. -->
+    <magic>
+      <match type="string" offset="0" value="ISX "/>
+    </magic>
+  </mime-type>
 </mime-info>

Makefile

@@ -205,18 +205,39 @@ SDL_LDFLAGS += -lopenal
 endif
 SDL_AUDIO_DRIVERS += openal
 endif
-else
+else # ifneq ($(PKG_CONFIG),)
 SDL_CFLAGS := $(shell $(PKG_CONFIG) --cflags sdl2)
 SDL_LDFLAGS := $(shell $(PKG_CONFIG) --libs sdl2) -lpthread
 
 # Allow OpenAL to be disabled even if the development libraries are available
 ifneq ($(ENABLE_OPENAL),0)
-ifeq ($(shell $(PKG_CONFIG) --exists openal && echo 0),0)
+ifneq ($(shell $(PKG_CONFIG) --exists openal && echo 0),)
 SDL_CFLAGS += $(shell $(PKG_CONFIG) --cflags openal) -DENABLE_OPENAL
 SDL_LDFLAGS += $(shell $(PKG_CONFIG) --libs openal)
 SDL_AUDIO_DRIVERS += openal
 endif
 endif
+
+ifneq ($(shell $(PKG_CONFIG) --exists gio-unix-2.0 || echo 0),)
+GIO_CFLAGS = $(error The Gio library could not be found)
+GIO_LDFLAGS = $(error The Gio library could not be found)
+else
+GIO_CFLAGS := $(shell $(PKG_CONFIG) --cflags gio-unix-2.0) -DG_LOG_USE_STRUCTURED
+GIO_LDFLAGS := $(shell $(PKG_CONFIG) --libs gio-unix-2.0)
+ifeq ($(CONF),debug)
+GIO_CFLAGS += -DG_ENABLE_DEBUG
+else
+GIO_CFLAGS += -DG_DISABLE_ASSERT
+endif
+endif
+
+ifneq ($(shell $(PKG_CONFIG) --exists gdk-pixbuf-2.0 || echo 0),)
+GDK_PIXBUF_CFLAGS = $(error The Gdk-Pixbuf library could not be found)
+GDK_PIXBUF_LDFLAGS = $(error The Gdk-Pixbuf library could not be found)
+else
+GDK_PIXBUF_CFLAGS := $(shell $(PKG_CONFIG) --cflags gdk-pixbuf-2.0)
+GDK_PIXBUF_LDFLAGS := $(shell $(PKG_CONFIG) --libs gdk-pixbuf-2.0)
+endif
 endif
 
 ifeq (,$(PKG_CONFIG))
@@ -330,6 +351,7 @@ endif
 
 cocoa: $(BIN)/SameBoy.app
 quicklook: $(BIN)/SameBoy.qlgenerator
+xdg-thumbnailer: $(BIN)/XdgThumbnailer/sameboy-thumbnailer
 sdl: $(SDL_TARGET) $(BIN)/SDL/dmg_boot.bin $(BIN)/SDL/mgb_boot.bin $(BIN)/SDL/cgb0_boot.bin $(BIN)/SDL/cgb_boot.bin $(BIN)/SDL/agb_boot.bin $(BIN)/SDL/sgb_boot.bin $(BIN)/SDL/sgb2_boot.bin $(BIN)/SDL/LICENSE $(BIN)/SDL/registers.sym $(BIN)/SDL/background.bmp $(BIN)/SDL/Shaders $(BIN)/SDL/Palettes
 bootroms: $(BIN)/BootROMs/agb_boot.bin $(BIN)/BootROMs/cgb_boot.bin $(BIN)/BootROMs/cgb0_boot.bin $(BIN)/BootROMs/dmg_boot.bin $(BIN)/BootROMs/mgb_boot.bin $(BIN)/BootROMs/sgb_boot.bin $(BIN)/BootROMs/sgb2_boot.bin
 tester: $(TESTER_TARGET) $(BIN)/tester/dmg_boot.bin $(BIN)/tester/cgb_boot.bin $(BIN)/tester/agb_boot.bin $(BIN)/tester/sgb_boot.bin $(BIN)/tester/sgb2_boot.bin
@@ -345,6 +367,9 @@ all: sdl tester libretro lib
 ifeq ($(PLATFORM),Darwin)
 all: cocoa ios-ipa ios-deb
 endif
+ifneq ($(FREEDESKTOP),)
+all: xdg-thumbnailer
+endif
 
 # Get a list of our source files and their respective object file targets
 
@@ -355,6 +380,7 @@ TESTER_SOURCES := $(shell ls Tester/*.c)
 IOS_SOURCES := $(filter-out iOS/installer.m, $(shell ls iOS/*.m)) $(shell ls AppleCommon/*.m)
 COCOA_SOURCES := $(shell ls Cocoa/*.m) $(shell ls HexFiend/*.m) $(shell ls JoyKit/*.m) $(shell ls AppleCommon/*.m)
 QUICKLOOK_SOURCES := $(shell ls QuickLook/*.m) $(shell ls QuickLook/*.c)
+XDG_THUMBNAILER_SOURCES := $(shell ls XdgThumbnailer/*.c)
 
 ifeq ($(PLATFORM),windows32)
 CORE_SOURCES += $(shell ls Windows/*.c)
@@ -367,6 +393,7 @@ IOS_OBJECTS := $(patsubst %,$(OBJ)/%.o,$(IOS_SOURCES))
 QUICKLOOK_OBJECTS := $(patsubst %,$(OBJ)/%.o,$(QUICKLOOK_SOURCES))
 SDL_OBJECTS := $(patsubst %,$(OBJ)/%.o,$(SDL_SOURCES))
 TESTER_OBJECTS := $(patsubst %,$(OBJ)/%.o,$(TESTER_SOURCES))
+XDG_THUMBNAILER_OBJECTS := $(patsubst %,$(OBJ)/%.o,$(XDG_THUMBNAILER_SOURCES)) $(OBJ)/XdgThumbnailer/resources.c.o
 
 lib: $(PUBLIC_HEADERS)
 
@@ -410,9 +437,25 @@ $(OBJ)/SDL/%.c.o: SDL/%.c
 	-@$(MKDIR) -p $(dir $@)
 	$(CC) $(CFLAGS) $(FRONTEND_CFLAGS) $(FAT_FLAGS) $(SDL_CFLAGS) $(GL_CFLAGS) -c $< -o $@
 
+$(OBJ)/XdgThumbnailer/%.c.o: XdgThumbnailer/%.c
+	-@$(MKDIR) -p $(dir $@)
+	$(CC) $(CFLAGS) $(GIO_CFLAGS) $(GDK_PIXBUF_CFLAGS) -DG_LOG_DOMAIN='"sameboy-thumbnailer"' -c $< -o $@
+# Make sure not to attempt compiling this before generating the resource code.
+$(OBJ)/XdgThumbnailer/emulate.c.o: $(OBJ)/XdgThumbnailer/resources.h
+# Silence warnings for this. It is code generated not by us, so we do not want `-Werror` to break
+# compilation with some version of the generator and/or compiler.
+$(OBJ)/XdgThumbnailer/%.c.o: $(OBJ)/XdgThumbnailer/%.c
+	-@$(MKDIR) -p $(dir $@)
+	$(CC) $(CFLAGS) $(GIO_CFLAGS) $(GDK_PIXBUF_CFLAGS) -DG_LOG_DOMAIN='"sameboy-thumbnailer"' -w -c $< -o $@
+
+$(OBJ)/XdgThumbnailer/resources.c $(OBJ)/XdgThumbnailer/resources.h: %: XdgThumbnailer/resources.gresource.xml $(BIN)/BootROMs/cgb_boot_fast.bin
+	-@$(MKDIR) -p $(dir $@)
+	CC=$(CC) glib-compile-resources --dependency-file $@.mk --generate-phony-targets --generate --target $@ $<
+-include $(OBJ)/XdgThumbnailer/resources.c.mk $(OBJ)/XdgThumbnailer/resources.h.mk
+
 $(OBJ)/OpenDialog/%.c.o: OpenDialog/%.c
 	-@$(MKDIR) -p $(dir $@)
-	$(CC) $(CFLAGS) $(FRONTEND_CFLAGS) $(FAT_FLAGS) $(SDL_CFLAGS) $(GL_CFLAGS) -c $< -o $@
+	$(CC) $(CFLAGS) $(SDL_CFLAGS) $(GL_CFLAGS) -c $< -o $@
 
 
 $(OBJ)/%.c.o: %.c
@@ -427,7 +470,7 @@ $(OBJ)/HexFiend/%.m.o: HexFiend/%.m
 $(OBJ)/%.m.o: %.m
 	-@$(MKDIR) -p $(dir $@)
 	$(CC) $(CFLAGS) $(FRONTEND_CFLAGS) $(FAT_FLAGS) $(OCFLAGS) -c $< -o $@
-    
+
 # iOS Port
 
 $(BIN)/SameBoy-iOS.app: $(BIN)/SameBoy-iOS.app/SameBoy \
@@ -530,7 +573,13 @@ endif
 $(BIN)/SameBoy.qlgenerator/Contents/Resources/cgb_boot_fast.bin: $(BIN)/BootROMs/cgb_boot_fast.bin
 	-@$(MKDIR) -p $(dir $@)
 	cp -f $^ $@
-	
+
+# XDG thumbnailer
+
+$(BIN)/XdgThumbnailer/sameboy-thumbnailer: $(CORE_OBJECTS) $(XDG_THUMBNAILER_OBJECTS)
+	-@$(MKDIR) -p $(dir $@)
+	$(CC) $^ -o $@ $(LDFLAGS) $(GIO_LDFLAGS) $(GDK_PIXBUF_LDFLAGS)
+
 # SDL Port
 
 # Unix versions build only one binary
@@ -584,41 +633,43 @@ $(BIN)/tester/sameboy_tester.exe: $(CORE_OBJECTS) $(SDL_OBJECTS)
 	-@$(MKDIR) -p $(dir $@)
 	$(CC) $^ -o $@ $(LDFLAGS) -Wl,/subsystem:console
 
-$(BIN)/SDL/%.bin: $(BOOTROMS_DIR)/%.bin
-	-@$(MKDIR) -p $(dir $@)
-	cp -f $^ $@
-
 $(BIN)/tester/%.bin: $(BOOTROMS_DIR)/%.bin
 	-@$(MKDIR) -p $(dir $@)
-	cp -f $^ $@
+	cp -f $< $@
 
 $(BIN)/SameBoy.app/Contents/Resources/%.bin: $(BOOTROMS_DIR)/%.bin
 	-@$(MKDIR) -p $(dir $@)
-	cp -f $^ $@
+	cp -f $< $@
 
 $(BIN)/SameBoy-iOS.app/%.bin: $(BOOTROMS_DIR)/%.bin
 	-@$(MKDIR) -p $(dir $@)
-	cp -f $^ $@
+	cp -f $< $@
+
+$(BIN)/SDL/%.bin: $(BOOTROMS_DIR)/%.bin
+	-@$(MKDIR) -p $(dir $@)
+	cp -f $< $@
 
 $(BIN)/SDL/LICENSE: LICENSE
 	-@$(MKDIR) -p $(dir $@)
-	grep -v "^  " $^ > $@
+	grep -v "^  " $< > $@
 
 $(BIN)/SDL/registers.sym: Misc/registers.sym
 	-@$(MKDIR) -p $(dir $@)
-	cp -f $^ $@
+	cp -f $< $@
 
 $(BIN)/SDL/background.bmp: SDL/background.bmp
 	-@$(MKDIR) -p $(dir $@)
-	cp -f $^ $@
+	cp -f $< $@
 
-$(BIN)/SDL/Shaders: Shaders
+$(BIN)/SDL/Shaders: $(wildcard Shaders/*.fsh)
 	-@$(MKDIR) -p $@
-	cp -rf Shaders/*.fsh $@
+	cp -f $^ $@
-    
+	touch $@
+
 $(BIN)/SDL/Palettes: Misc/Palettes
 	-@$(MKDIR) -p $@
-	cp -rf Misc/Palettes/*.sbp $@
+	cp -f $</* $@
+	touch $@
 
 # Boot ROMs
 
@@ -647,54 +698,37 @@ $(BIN)/BootROMs/%.bin: BootROMs/%.asm $(OBJ)/BootROMs/SameBoyLogo.pb12
 
 # Libretro Core (uses its own build system)
 libretro:
-	CFLAGS="$(WARNINGS)" $(MAKE) -C libretro BOOTROMS_DIR=$(abspath $(BOOTROMS_DIR)) BIN=$(abspath $(BIN))
+	CC=$(CC) CFLAGS="$(WARNINGS)" $(MAKE) -C libretro BOOTROMS_DIR=$(abspath $(BOOTROMS_DIR)) BIN=$(abspath $(BIN))
 
-# install for Linux/FreeDesktop/etc.
+# Install for Linux, and other FreeDesktop platforms.
-# Does not install mimetype icons because FreeDesktop is cursed abomination with no right to exist.
-# If you somehow find a reasonable way to make associate an icon with an extension in this dumpster
-# fire of a desktop environment, open an issue or a pull request
 ifneq ($(FREEDESKTOP),)
-ICON_NAMES := apps/sameboy mimetypes/x-gameboy-rom mimetypes/x-gameboy-color-rom
+install: $(BIN)/XdgThumbnailer/sameboy-thumbnailer sdl $(shell find FreeDesktop) XdgThumbnailer/sameboy.thumbnailer
-ICON_SIZES := 16x16 32x32 64x64 128x128 256x256 512x512
+	(cd $(BIN)/SDL && find . \! -name sameboy -type f -exec install -Dm 644 -T {} "$(DESTDIR)$(DATA_DIR)/{}" \; )
-ICONS := $(foreach name,$(ICON_NAMES), $(foreach size,$(ICON_SIZES),$(DESTDIR)$(PREFIX)/share/icons/hicolor/$(size)/$(name).png))
+	install -Dm 755 -s $(BIN)/SDL/sameboy $(DESTDIR)$(PREFIX)/bin/sameboy
-install: sdl $(DESTDIR)$(PREFIX)/share/mime/packages/sameboy.xml $(ICONS) FreeDesktop/sameboy.desktop
+	install -Dm 755 -s $(BIN)/XdgThumbnailer/sameboy-thumbnailer $(DESTDIR)$(PREFIX)/bin/sameboy-thumbnailer
-	-@$(MKDIR) -p $(dir $(DESTDIR)$(PREFIX))
+	install -Dm 644 XdgThumbnailer/sameboy.thumbnailer $(DESTDIR)$(PREFIX)/share/thumbnailers/sameboy.thumbnailer
-	mkdir -p $(DESTDIR)$(DATA_DIR)/ $(DESTDIR)$(PREFIX)/bin/
-	cp -rf $(BIN)/SDL/* $(DESTDIR)$(DATA_DIR)/
-	mv $(DESTDIR)$(DATA_DIR)/sameboy $(DESTDIR)$(PREFIX)/bin/sameboy
 ifeq ($(DESTDIR),)
-	-update-mime-database -n $(PREFIX)/share/mime
+	xdg-mime install --novendor FreeDesktop/sameboy.xml
-	-xdg-desktop-menu install --novendor --mode system FreeDesktop/sameboy.desktop
+	xdg-desktop-menu install --novendor FreeDesktop/sameboy.desktop
-	-xdg-icon-resource forceupdate --mode system
+	for size in 16 32 64 128 256 512; do \
-	-xdg-desktop-menu forceupdate --mode system
+		xdg-icon-resource install --novendor --theme hicolor --size $$size --context apps FreeDesktop/AppIcon/$${size}x$${size}.png sameboy; \
-ifneq ($(SUDO_USER),)
+		xdg-icon-resource install --novendor --theme hicolor --size $$size --context mimetypes FreeDesktop/Cartridge/$${size}x$${size}.png x-gameboy-rom; \
-	-su $(SUDO_USER) -c "xdg-desktop-menu forceupdate --mode system"
+		xdg-icon-resource install --novendor --theme hicolor --size $$size --context mimetypes FreeDesktop/ColorCartridge/$${size}x$${size}.png x-gameboy-color-rom; \
-endif
+	done
 else
-	-@$(MKDIR) -p $(DESTDIR)$(PREFIX)/share/applications/
+	install -Dm 644 FreeDesktop/sameboy.xml $(DESTDIR)$(PREFIX)/share/mime/sameboy.xml
-	cp FreeDesktop/sameboy.desktop $(DESTDIR)$(PREFIX)/share/applications/sameboy.desktop
+	install -Dm 644 FreeDesktop/sameboy.desktop $(DESTDIR)$(PREFIX)/share/applications/sameboy.desktop
+	for size in 16x16 32x32 64x64 128x128 256x256 512x512; do \
+		install -Dm 644 FreeDesktop/AppIcon/$$size.png $(DESTDIR)$(PREFIX)/share/icons/hicolor/$$size/apps/sameboy.png; \
+		install -Dm 644 FreeDesktop/Cartridge/$$size.png $(DESTDIR)$(PREFIX)/share/icons/hicolor/$$size/mimetypes/x-gameboy-rom.png; \
+		install -Dm 644 FreeDesktop/ColorCartridge/$$size.png $(DESTDIR)$(PREFIX)/share/icons/hicolor/$$size/mimetypes/x-gameboy-color-rom.png; \
+	done
 endif
-
-$(DESTDIR)$(PREFIX)/share/icons/hicolor/%/apps/sameboy.png: FreeDesktop/AppIcon/%.png
-	-@$(MKDIR) -p $(dir $@)
-	cp -f $^ $@
-
-$(DESTDIR)$(PREFIX)/share/icons/hicolor/%/mimetypes/x-gameboy-rom.png: FreeDesktop/Cartridge/%.png
-	-@$(MKDIR) -p $(dir $@)
-	cp -f $^ $@
-
-$(DESTDIR)$(PREFIX)/share/icons/hicolor/%/mimetypes/x-gameboy-color-rom.png: FreeDesktop/ColorCartridge/%.png
-	-@$(MKDIR) -p $(dir $@)
-	cp -f $^ $@
-
-$(DESTDIR)$(PREFIX)/share/mime/packages/sameboy.xml: FreeDesktop/sameboy.xml
-	-@$(MKDIR) -p $(dir $@)
-	cp -f $^ $@
 endif
 
 ios:
 	@$(MAKE) _ios
-    
+
 $(BIN)/SameBoy-iOS.ipa: ios iOS/sideload.entitlements
 	$(MKDIR) -p $(OBJ)/Payload
 	cp -rf $(BIN)/SameBoy-iOS.app $(OBJ)/Payload/SameBoy-iOS.app
@@ -702,7 +736,7 @@ $(BIN)/SameBoy-iOS.ipa: ios iOS/sideload.entitlements
 	(cd $(OBJ) && zip -q $(abspath $@) -r Payload)
 	rm -rf $(OBJ)/Payload
 
-    
+
 $(BIN)/SameBoy-iOS.deb: $(OBJ)/debian-binary $(OBJ)/control.tar.gz $(OBJ)/data.tar.gz
 	-@$(MKDIR) -p $(dir $@)
 	(cd $(OBJ) && ar cr $(abspath $@) $(notdir $^))

XdgThumbnailer/emulate.c

@@ -0,0 +1,101 @@
+#include "emulate.h"
+
+#include <glib.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "Core/gb.h"
+
+// Auto-generated via `glib-compile-resources` from `resources.gresource.xml`.
+#include "build/obj/XdgThumbnailer/resources.h"
+
+#define NB_FRAMES_TO_EMULATE (60 * 10)
+
+#define BOOT_ROM_SIZE (0x100 + 0x800) // The two "parts" of it, which are stored contiguously.
+
+/* --- */
+
+static char *async_input_callback(GB_gameboy_t *gb)
+{
+    (void)gb;
+    return NULL;
+}
+
+static void log_callback(GB_gameboy_t *gb, const char *string, GB_log_attributes attributes)
+{
+    (void)gb, (void)string, (void)attributes; // Swallow any logs.
+}
+
+static void vblank_callback(GB_gameboy_t *gb, GB_vblank_type_t type)
+{
+    (void)type; // Ignore the type, we use VBlank counting as a kind of pacing (and to avoid tearing).
+
+    unsigned *nb_frames_left = GB_get_user_data(gb);
+    (*nb_frames_left)--;
+
+    // *Do* render the very last frame.
+    if (*nb_frames_left == 1) {
+        GB_set_rendering_disabled(gb, false);
+    }
+}
+
+static uint32_t rgb_encode(GB_gameboy_t *gb, uint8_t r, uint8_t g, uint8_t b)
+{
+    uint32_t rgba;
+    // The GdkPixbuf that will be created from the screen buffer later, expects components in the
+    // order [red, green, blue, alpha], from a uint8_t[] buffer.
+    // But SameBoy requires a uint32_t[] buffer, and don't know the endianness of `uint32_t`.
+    // So we treat each uint32_t as a 4-byte buffer, and write the bytes accordingly.
+    // This is guaranteed to not be UB, because casting a `T*` to any flavour of `char*` accesses
+    // and modifies the `T`'s "object representation".
+    uint8_t *bytes = (uint8_t *)&rgba;
+    bytes[0] = r;
+    bytes[1] = g;
+    bytes[2] = b;
+    bytes[3] = 0xFF;
+    return rgba;
+}
+
+uint8_t emulate(const char *path, uint32_t screen[static GB_SCREEN_WIDTH * GB_SCREEN_HEIGHT])
+{
+    GB_gameboy_t gb;
+    GB_init(&gb, GB_MODEL_CGB_E);
+
+    const char *last_dot = strrchr(path, '.');
+    bool is_isx = last_dot && strcmp(last_dot + 1, "isx") == 0;
+    if (is_isx ? GB_load_isx(&gb, path) : GB_load_rom(&gb, path)) {
+        exit(EXIT_FAILURE);
+    }
+
+    GError *error = NULL;
+    GBytes *boot_rom = g_resource_lookup_data(resources_get_resource(), "/thumbnailer/cgb_boot_fast.bin",
+                                              G_RESOURCE_LOOKUP_FLAGS_NONE, &error);
+    g_assert_no_error(error); // This shouldn't be able to fail.
+    size_t boot_rom_size;
+    const uint8_t *boot_rom_data = g_bytes_get_data(boot_rom, &boot_rom_size);
+    g_assert_cmpuint(boot_rom_size, ==, BOOT_ROM_SIZE);
+    GB_load_boot_rom_from_buffer(&gb, boot_rom_data, boot_rom_size);
+    g_bytes_unref(boot_rom);
+
+    GB_set_vblank_callback(&gb, vblank_callback);
+    GB_set_pixels_output(&gb, screen);
+    GB_set_rgb_encode_callback(&gb, rgb_encode);
+    GB_set_async_input_callback(&gb, async_input_callback);
+    GB_set_log_callback(&gb, log_callback); // Anything bizarre the ROM does during emulation, we don't care about.
+    GB_set_color_correction_mode(&gb, GB_COLOR_CORRECTION_MODERN_BALANCED);
+
+    unsigned nb_frames_left = NB_FRAMES_TO_EMULATE;
+    GB_set_user_data(&gb, &nb_frames_left);
+
+    GB_set_rendering_disabled(&gb, true);
+    GB_set_turbo_mode(&gb, true, true);
+    while (nb_frames_left) {
+        GB_run(&gb);
+    }
+
+    int cgb_flag = GB_read_memory(&gb, 0x143) & 0xC0;
+    GB_free(&gb);
+    return cgb_flag;
+}

XdgThumbnailer/emulate.h

@@ -0,0 +1,8 @@
+#pragma once
+
+#include <stdint.h>
+
+#define GB_SCREEN_WIDTH 160
+#define GB_SCREEN_HEIGHT 144
+
+uint8_t emulate(const char *path, uint32_t screen[static GB_SCREEN_WIDTH * GB_SCREEN_HEIGHT]);

XdgThumbnailer/main.c

@@ -0,0 +1,130 @@
+#include <errno.h>
+#include <gdk-pixbuf/gdk-pixbuf.h>
+#include <glib.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "emulate.h"
+
+static const char dmg_only_resource_path[] = "/thumbnailer/CartridgeTemplate.png";
+static const char dual_resource_path[] = "/thumbnailer/UniversalCartridgeTemplate.png";
+static const char cgb_only_resource_path[] = "/thumbnailer/ColorCartridgeTemplate.png";
+
+static GdkPixbuf *generate_thumbnail(const char *input_path)
+{
+    uint32_t screen_raw[GB_SCREEN_WIDTH * GB_SCREEN_HEIGHT];
+    uint8_t cgb_flag = emulate(input_path, screen_raw);
+
+    // Generate the thumbnail from `screen_raw` and `cgb_flag`.
+
+    // `screen_raw` is properly formatted for this operation; see the comment in `rgb_encode` for a
+    // discussion of why and how.
+    GdkPixbuf *screen = gdk_pixbuf_new_from_data((uint8_t *)screen_raw, GDK_COLORSPACE_RGB,
+                                                 true,                                    // Yes, we have alpha!
+                                                 8,                                       // bpp
+                                                 GB_SCREEN_WIDTH, GB_SCREEN_HEIGHT,       // Size.
+                                                 GB_SCREEN_WIDTH * sizeof(screen_raw[0]), // Row stride.
+                                                 NULL, NULL);                             // Do not free the buffer.
+    // Scale the screen and position it in the appropriate place for compositing the cartridge templates.
+    GdkPixbuf *scaled_screen = gdk_pixbuf_new(GDK_COLORSPACE_RGB, true, 8, 1024, 1024);
+    gdk_pixbuf_scale(screen,                                    // Source.
+                     scaled_screen,                             // Destination.
+                     192, 298,                                  // Match the displacement below.
+                     GB_SCREEN_WIDTH * 4, GB_SCREEN_HEIGHT * 4, // How the scaled rectangle should be cropped.
+                     192, 298, // Displace the scaled screen so it lines up with the template.
+                     4, 4,     // Scaling factors.
+                     GDK_INTERP_NEAREST);
+    g_object_unref(screen);
+
+    GError *error = NULL;
+    GdkPixbuf *template;
+    switch (cgb_flag) {
+        case 0xC0:
+            template = gdk_pixbuf_new_from_resource(cgb_only_resource_path, &error);
+            break;
+        case 0x80:
+            template = gdk_pixbuf_new_from_resource(dual_resource_path, &error);
+            break;
+        default:
+            template = gdk_pixbuf_new_from_resource(dmg_only_resource_path, &error);
+            break;
+    }
+    g_assert_no_error(error);
+    g_assert_cmpint(gdk_pixbuf_get_width(template), ==, 1024);
+    g_assert_cmpint(gdk_pixbuf_get_height(template), ==, 1024);
+    gdk_pixbuf_composite(template,           // Source.
+                         scaled_screen,      // Destination.
+                         0, 0,               // Match the displacement below.
+                         1024, 1024,         // Crop of the scaled rectangle.
+                         0, 0,               // Displacement of the scaled rectangle.
+                         1, 1,               // Scaling factors.
+                         GDK_INTERP_NEAREST, // Doesn't really matter, but should be a little faster.
+                         255);               // Blending factor of the source onto the destination.
+    g_object_unref(template);
+
+    return scaled_screen;
+}
+
+static GdkPixbuf *enforce_max_size(GdkPixbuf *thumbnail, unsigned max_size)
+{
+    g_assert_cmpuint(gdk_pixbuf_get_width(thumbnail), ==, gdk_pixbuf_get_height(thumbnail));
+    g_assert_cmpuint(gdk_pixbuf_get_width(thumbnail), ==, 1024);
+    // This is only a *max* size; don't bother scaling up.
+    // (This also prevents any overflow errors—notice that the scale function takes `int` size parameters!)
+    if (max_size > 1024) return thumbnail;
+    GdkPixbuf *scaled = gdk_pixbuf_scale_simple(thumbnail, max_size, max_size, GDK_INTERP_BILINEAR);
+    g_object_unref(thumbnail);
+    return scaled;
+}
+
+static void write_thumbnail(GdkPixbuf *thumbnail, const char *output_path)
+{
+    GError *error = NULL;
+    // Intentionally be "not a good citizen":
+    // - Write directly to the provided path, instead of atomically replacing it with a fully-formed file;
+    //   this is necessary for at least Tumbler (XFCE's thumbnailer daemon), which creates the file **and** keeps the
+    //   returned FD—which keeps pointing to the deleted file... which is still empty!
+    // - Do not save any metadata to the PNG, since the thumbnailer daemon (again, at least XFCE's, the only one I have
+    //   tested with) appears to read the PNG's pixels, and write a new one with the appropriate metadata.
+    //   (Thank you! Saves me all that work.)
+    gdk_pixbuf_save(thumbnail, output_path, "png", &error, NULL);
+    if (error) {
+        g_error("Failed to save thumbnail: %s", error->message);
+        // NOTREACHED
+    }
+}
+
+int main(int argc, char *argv[])
+{
+    if (argc != 3 && argc != 4) {
+        g_error("Usage: %s <input path> <output path> [<size>]", argv[0] ? argv[0] : "sameboy-thumbnailer");
+        // NOTREACHED
+    }
+    const char *input_path = argv[1];
+    char *output_path = argv[2];    // Gets mutated in-place.
+    const char *max_size = argv[3]; // May be NULL.
+
+    g_debug("%s -> %s [%s]", input_path, output_path, max_size ? max_size : "(none)");
+
+    GdkPixbuf *thumbnail = generate_thumbnail(input_path);
+    if (max_size) {
+        char *endptr;
+        errno = 0;
+        /* This will implicitly truncate, but enforce_max_size will cap size to 1024 anyway.
+           (Not that 4 billion pixels wide icons make sense to begin with)*/
+        unsigned size = strtoul(max_size, &endptr, 10);
+        if (errno != 0 || *max_size == '\0' || *endptr != '\0') {
+            g_error("Invalid size parameter \"%s\": %s", max_size, strerror(errno == 0 ? EINVAL : errno));
+            // NOTREACHED
+        }
+
+        thumbnail = enforce_max_size(thumbnail, size);
+    }
+    write_thumbnail(thumbnail, output_path);
+    g_object_unref(thumbnail);
+
+    return 0;
+}

XdgThumbnailer/resources.gresource.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<gresources>
+	<gresource prefix="/thumbnailer">
+		<file alias="CartridgeTemplate.png">QuickLook/CartridgeTemplate.png</file>
+		<file alias="ColorCartridgeTemplate.png">QuickLook/ColorCartridgeTemplate.png</file>
+		<file alias="UniversalCartridgeTemplate.png">QuickLook/UniversalCartridgeTemplate.png</file>
+		<file alias="cgb_boot_fast.bin">build/bin/BootROMs/cgb_boot_fast.bin</file>
+	</gresource>
+</gresources>

XdgThumbnailer/sameboy.thumbnailer

@@ -0,0 +1,4 @@
+[Thumbnailer Entry]
+TryExec=sameboy-thumbnailer
+Exec=sameboy-thumbnailer %i %o %s
+MimeType=application/x-gameboy-rom;application/x-gameboy-color-rom;application/x-gameboy-isx