mkpng

#!/bin/bash

## Generates PNG drawables from all SVG files.

SVG_PATH=./extra

LDPI_PATH=./res/drawable-ldpi
MDPI_PATH=./res/drawable-mdpi
HDPI_PATH=./res/drawable-hdpi
XHDPI_PATH=./res/drawable-xhdpi
XXHDPI_PATH=./res/drawable-xxhdpi

# Android density bins are:
# LDPI:   120 dpi
# MDPI:   160 dpi
# HDPI:   240 dpi
# XHDPI:  320 dpi
# XXHDPI: 480 dpi

# Default for icons is 1 SVG user unit ("px") = 1 dp.
# However, both these units have their own conflicting definitions:
# - 1 SVG user units = 1 pixel at 90 dpi.
# - 1 dp = 1 pixel at MDPI (160 dpi).
# Therefore, SVG export needs to use the following dpi values:

LDPI_RES=67.5
MDPI_RES=90
HDPI_RES=135
XHDPI_RES=180
XXHDPI_RES=270


## Creates a single PNG file from a given input SVG file at the given DPI resolution.
##
## If the output file exists and is newer than the input file, no action is taken.
##
## @param $1 The input SVG filename (full path)
## @param $2 The output PNG filename (full path)
## @param $3 The resolution in DPI
function make_png_dpi {
	if [[ -e $2 && $2 -nt $1 ]] ; then
		echo Skipping $1 because $2 exists and is newer
	else
		echo inkscape --without-gui --export-area-page --export-dpi=$3 --export-png=$2 $1
		inkscape --without-gui --export-area-page --export-dpi=$3 --export-png=$2 $1
	fi
}


## Creates a single PNG file from a given input SVG file at the given width.
##
## If the output file exists and is newer than the input file, no action is taken.
##
## @param $1 The input SVG filename (full path)
## @param $2 The output PNG filename (full path)
## @param $3 The width in pixels
function make_png_width {
	if [[ -e $2 && $2 -nt $1 ]] ; then
		echo Skipping $1 because $2 exists and is newer
	else
		echo inkscape --without-gui --export-area-page --export-width=$3 --export-png=$2 $1
		inkscape --without-gui --export-area-page --export-width=$3 --export-png=$2 $1
	fi
}


## Converts a SVG icon to PNG drawables using the default of 1 px = 1 dip.
##
## @param $1 The input SVG filename (path stripped)
## @param $2 The output PNG filename (path stripped)
function convert_by_dpi {
	baresvgfile=$1
	barepngfile=$2
	make_png_dpi $SVG_PATH/$baresvgfile $LDPI_PATH/$barepngfile $LDPI_RES
	make_png_dpi $SVG_PATH/$baresvgfile $MDPI_PATH/$barepngfile $MDPI_RES
	make_png_dpi $SVG_PATH/$baresvgfile $HDPI_PATH/$barepngfile $HDPI_RES
	make_png_dpi $SVG_PATH/$baresvgfile $XHDPI_PATH/$barepngfile $XHDPI_RES
	make_png_dpi $SVG_PATH/$baresvgfile $XXHDPI_PATH/$barepngfile $XXHDPI_RES
}


## Converts a SVG icon to PNG drawables using a specified width.
##
## @param $1 The input SVG filename (path stripped)
## @param $2 The output PNG filename (path stripped)
## @param $3 The width for the converted PNG files, in dip
function convert_by_width {
	baresvgfile=$1
	barepngfile=$2
    width_mdpi=$3
	# Derive other sizes from MDPI
	# Ordered to do lossy operations (integer division) last
	width_xhdpi=$(($width_mdpi * 2))
	width_xxhdpi=$(($width_mdpi * 3))
	width_hdpi=$(($width_xxhdpi / 2))
	width_ldpi=$(($width_hdpi / 2))
	make_png_width $SVG_PATH/$baresvgfile $LDPI_PATH/$barepngfile $width_ldpi
	make_png_width $SVG_PATH/$baresvgfile $MDPI_PATH/$barepngfile $width_mdpi
	make_png_width $SVG_PATH/$baresvgfile $HDPI_PATH/$barepngfile $width_hdpi
	make_png_width $SVG_PATH/$baresvgfile $XHDPI_PATH/$barepngfile $width_xhdpi
	make_png_width $SVG_PATH/$baresvgfile $XXHDPI_PATH/$barepngfile $width_xxhdpi
}


for svgfile in $SVG_PATH/*.svg
do
	# strip path from file name
	baresvgfile=${svgfile#$SVG_PATH/}
	barepngfile=${baresvgfile%.svg}.png
	case $baresvgfile in
		ic_context_marker_*.svg)
			convert_by_width $baresvgfile $barepngfile 32
			;;
		ic_launcher.svg|ic_launcher_oi_filemanager.svg)
			convert_by_width $baresvgfile $barepngfile 48
			;;
		*)
			convert_by_dpi $baresvgfile $barepngfile
	esac
done