#!/bin/bash
# SPDX-License-Identifier: GPL-2.0

# Script for Image Magick that writes the dss logo in png format
# to stdout.

set -u

width=320
height=110
border=5
radius1=4
radius2=5
circle_y=90
arrow_y=70
text_x=128
text_y=55
pointsize=36

declare -a circle arrow rectangle text

make_circles()
{
	local inner='stroke black fill red circle'
	local outer='stroke black fill black circle'
	local num=1
	local idx=0
	local y=$circle_y
	local step x0 i j idx num

	for ((i = 0; i < 4; i++)); do
		step=$(((width / 4 + num) / (num + 1)))
		x0=$((border + width / 4 * i))
		for ((j = 1; j <= $num; j++)); do
			x=$((x0 + j * $step))
			circle[$idx]='-draw'; let idx++
			circle[$idx]="$outer $x,$y,$((x + radius2)),$y"; let idx++
			circle[$idx]='-draw'; let idx++
			circle[$idx]="$inner $x,$y,$((x + radius1)),$y"; let idx++
		done
		num=$((num * 2))
	done
	#echo "${circle[@]}"; exit 0
}

make_arrow()
{
	local arrow_head='l -15,-5  +5,+5  -5,+5  +15,-5 z'
	local idx=0
	local x0 x1 y

	arrow[$idx]='-draw'; let idx++
	x0=$((3 * border)); x1=$((width - 2 * border))
	y=$arrow_y
	arrow[$idx]="stroke white line $x0,$y $x1,$y"; let idx++
	arrow[$idx]='-draw'; let idx++
	x0=$((width - 2 * border))
	arrow[$idx]="stroke white fill white path 'M $x0,$y $arrow_head'"
	#echo "${arrow[@]}"; exit 0
}

make_rectangles()
{
	local idx=0
	local x x0 x1 y y0 y1 i red_green color

	rectangle[$idx]='-draw'; let idx++
	x=$((width + 2 * border))
	y=$((height + 2 * border))
	rectangle[$idx]="stroke yellow fill yellow rectangle 0,0 $x,$y"; let idx++
	for ((i = 0; i < 4; i++)); do
		rectangle[$idx]='-draw'; let idx++
		red_green="$(printf '%02x' $(((3 - i) * 60)))"
		color="#${red_green}${red_green}ff"
		x0=$((border + i * width / 4)); x1=$((x0 + width / 4 - 1))
		y0=$border; y1=$((y0 + height))
		rectangle[$idx]="stroke $color fill $color rectangle $x0,$y0 $x1,$y1"
		let idx++
	done
	#echo "${rectangle[@]}"; exit 0
}

make_text()
{
	text=(-pointsize $pointsize -draw \
		"fill white text $text_x,$text_y DSS")
	#echo "${text[@]}"; exit 0
}

make_rectangles
make_arrow
make_circles
make_text

convert -size $((width + 2 * border))x$((height + 2 * border)) \
	-background none xc: \
	"${rectangle[@]}" \
	"${arrow[@]}" \
	"${circle[@]}" \
	"${text[@]}" \
	png:-