lualoader: allow graphical bits to be disabled with loader_gfx

Some people prefer the old ASCII art look and it's good to have a way
to confirm that the fallbacks still work right on systems that have a
functional framebuffer available. Add a loader_gfx loader.conf(5)
variable to disable the eager use of graphics for these use-cases.

While we're here, clean up the style in the area a little bit; the early
porting that I did to lualoader did a lot of redundant ~= nil that has
carried over into some of the later work.  We can drop some of that, and
also re-organize some of these variables to improve readability.

ziaee notes that the positioning of the orb is a bit off; this is due to
a change in positioning that happened in
1b4e1171315398dec ("loader: Fix orb position") to account for the image
dimensions.  This should be partially reverted to get it right; we
shouldn't assume that we can use the same shift in gfx-* definitions for
both the ASCII art and the associated image -- the {image, image_rl}
pair should be converted to something more like an fbimg or gfx table
that has the image, image width and a shift override to avoid messing
up the ASCII positioning when disabled (or with no graphics available).

Reviewed by:	imp, manu, ziaee (manpages)
Differential Revision:	https://reviews.freebsd.org/D50706

3 files changed, 23 insertions, 16 deletions

diff --git a/stand/defaults/loader.conf b/stand/defaults/loader.conf
index b1e87520a2d4..5d66708d30ef 100644
--- a/stand/defaults/loader.conf
+++ b/stand/defaults/loader.conf
@@ -105,6 +105,7 @@ efi_max_resolution="1x1"	# Set the max resolution for EFI loader to use:
 				# WidthxHeight (e.g. 1920x1080)
 #kernels="kernel kernel.old"	# Kernels to display in the boot menu
 kernels_autodetect="YES"	# Auto-detect kernel directories in /boot
+#loader_gfx="YES"		# Use graphical images when available
 #loader_logo="orbbw"		# Desired logo: orbbw, orb, fbsdbw, beastiebw, beastie, none
 #comconsole_speed="115200"	# Set the current serial console speed
 #console="vidconsole"		# A comma separated list of console(s)
diff --git a/stand/defaults/loader.conf.5 b/stand/defaults/loader.conf.5
index 807d8ae62e9a..021f68f2309e 100644
--- a/stand/defaults/loader.conf.5
+++ b/stand/defaults/loader.conf.5
@@ -21,7 +21,7 @@
 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
-.Dd February 9, 2025
+.Dd June 5, 2025
 .Dt LOADER.CONF 5
 .Os
 .Sh NAME
@@ -414,6 +414,12 @@ the beastie boot menu will be skipped.
 If set to
 .Dq NO ,
 the autoboot menu will not be displayed
+.It Va loader_gfx
+If set to
+.Dq NO ,
+the ASCII art version of the brand and logo will be used even if graphical
+versions are available.
+Additionally, the menu frame will be drawn with ASCII art as well.
 .It Va loader_logo Pq Dq Li orbbw
 Selects a desired logo in the beastie boot menu.
 Possible values are:
diff --git a/stand/lua/drawer.lua b/stand/lua/drawer.lua
index ee33ae753916..d4c6bf850e86 100644
--- a/stand/lua/drawer.lua
+++ b/stand/lua/drawer.lua
@@ -217,6 +217,13 @@ local function defaultframe()
 	return "double"
 end
 
+local function gfxenabled()
+	return (loader.getenv("loader_gfx") or "yes"):lower() ~= "no"
+end
+local function gfxcapable()
+	return core.isFramebufferConsole() and gfx.term_putimage
+end
+
 local function drawframe()
 	local x = menu_position.x - 3
 	local y = menu_position.y - 1
@@ -242,7 +249,7 @@ local function drawframe()
 	x = x + shift.x
 	y = y + shift.y
 
-	if core.isFramebufferConsole() and gfx.term_drawrect ~= nil then
+	if gfxenabled() and gfxcapable() then
 		gfx.term_drawrect(x, y, x + w, y + h)
 		return true
 	end
@@ -332,11 +339,9 @@ local function drawbrand()
 		y = y + branddef.shift.y
 	end
 
-	if core.isFramebufferConsole() and
-	    gfx.term_putimage ~= nil and
-	    branddef.image ~= nil then
-		if gfx.term_putimage(branddef.image, x, y, 0, 7, 0)
-		then
+	local gfx_requested = branddef.image and gfxenabled()
+	if gfx_requested and gfxcapable() then
+		if gfx.term_putimage(branddef.image, x, y, 0, 7, 0) then
 			return true
 		end
 	end
@@ -383,16 +388,11 @@ local function drawlogo()
 		y = y + logodef.shift.y
 	end
 
-	if core.isFramebufferConsole() and
-	    gfx.term_putimage ~= nil and
-	    logodef.image ~= nil then
-		local y1 = 15
+	local gfx_requested = logodef.image and gfxenabled()
+	if gfx_requested and gfxcapable() then
+		local y1 = logodef.image_rl or 15
 
-		if logodef.image_rl ~= nil then
-			y1 = logodef.image_rl
-		end
-		if gfx.term_putimage(logodef.image, x, y, 0, y + y1, 0)
-		then
+		if gfx.term_putimage(logodef.image, x, y, 0, y + y1, 0) then
 			return true
 		end
 	end