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fgdata/Nasal/canvas/svg.nas
Stuart Buchanan 45b97601f2 Handle unusual use of - in .svg files 
Previously valid SVG strings such as
m 547.56916,962.17731 c 10e-6,25.66886
M831,144.861c-0.236,0.087-0.423,0.255-0.629,

would fail to parse.

Fix by Henning STALHKE
2020-08-19 20:09:06 +01:00

757 lines
21 KiB
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# Parse an xml file into a canvas group element
#
# @param group The canvas.Group instance to append the parsed elements to
# @param path The path of the svg file (absolute or relative to FG_ROOT)
# @param options Optional hash of options
# font-mapper func
# parse_images bool
var parsesvg = func(group, path, options = nil)
{
if( !isa(group, Group) )
die("Invalid argument group (type != Group)");
if( options == nil )
options = {};
if (!ishash(options)) {
die("Options need to be of type hash!");
}
# resolve paths using standard SimGear logic
var file_path = resolvepath(path);
if (file_path == "")
die("File not found: "~path);
path = file_path;
var logpr = func(level, msg)
{
logprint(level, "parsesvg: "~msg~" [path='"~ path~"']");
};
# Helper to get number without unit (eg. px)
var evalCSSNum = func(css_num)
{
if( css_num.ends_with("px") )
return substr(css_num, 0, size(css_num) - 2);
else if( css_num.ends_with("%") )
return substr(css_num, 0, size(css_num) - 1) / 100;
return css_num;
}
var level = 0;
var skip = 0;
var stack = [group];
var close_stack = []; # helper for check tag closing
var defs_stack = [];
var text = nil;
var tspans = nil;
# lookup table for element ids (for <use> element)
var id_dict = {};
# lookup table for mask and clipPath element ids
var clip_dict = {};
var cur_clip = nil;
# ----------------------------------------------------------------------------
# Create a new child an push it onto the stack
var pushElement = func(type, id = nil)
{
append(stack, stack[-1].createChild(type, id));
append(close_stack, level);
if (isscalar(id) and size(id)) {
id_dict[ id ] = stack[-1];
}
if( cur_clip != nil )
{
if(cur_clip['x'] != nil and cur_clip['y'] != nil
and cur_clip['width'] != nil and cur_clip['height'] != nil ) {
stack[-1].setClipByBoundingBox(cur_clip['x'], cur_clip['y'],
cur_clip['x'] + cur_clip['width'], cur_clip['y'] + cur_clip['height']);
}
else {
logpr(LOG_WARN, "Invalid or unsupported clip for element '" ~ id ~ "'");
}
cur_clip = nil;
}
}
# ----------------------------------------------------------------------------
# Remove the topmost element from the stack
var popElement = func
{
stack[-1].updateCenter();
# Create rotation matrix after all SVG defined transformations
stack[-1].set("tf-rot-index", stack[-1].createTransform()._node.getIndex());
pop(stack);
pop(close_stack);
}
# ----------------------------------------------------------------------------
# Parse a transformation (matrix)
# http://www.w3.org/TR/SVG/coords.html#TransformAttribute
var parseTransform = func(tf)
{
if( tf == nil )
return;
var end = 0;
while(1)
{
var start_type = tf.find_first_not_of("\t\n ", end);
if( start_type < 0 )
break;
var end_type = tf.find_first_of("(\t\n ", start_type + 1);
if( end_type < 0 )
break;
var start_args = tf.find('(', end_type);
if( start_args < 0 )
break;
var values = [];
end = start_args + 1;
while(1)
{
var start_num = tf.find_first_not_of(",\t\n ", end);
if( start_num < 0 )
break;
if( tf[start_num] == `)` )
break;
end = tf.find_first_of("),\t\n ", start_num + 1);
if( end < 0 )
break;
append(values, substr(tf, start_num, end - start_num));
}
if( end > 0 )
end += 1;
var type = substr(tf, start_type, end_type - start_type);
# TODO should we warn if to much/wrong number of arguments given?
if( type == "translate" )
{
# translate(<tx> [<ty>]), which specifies a translation by tx and ty. If
# <ty> is not provided, it is assumed to be zero.
stack[-1].createTransform().setTranslation
(
values[0],
size(values) > 1 ? values[1] : 0,
);
}
else if( type == "scale" )
{
# scale(<sx> [<sy>]), which specifies a scale operation by sx and sy. If
# <sy> is not provided, it is assumed to be equal to <sx>.
stack[-1].createTransform().setScale(values);
}
else if( type == "rotate" )
{
# rotate(<rotate-angle> [<cx> <cy>]), which specifies a rotation by
# <rotate-angle> degrees about a given point.
stack[-1].createTransform().setRotation
(
values[0] * D2R, # internal functions use rad
size(values) > 1 ? values[1:] : nil
);
}
else if( type == "matrix" )
{
if( size(values) == 6 )
stack[-1].createTransform(values);
else
logpr(LOG_WARN,
"Invalid arguments to matrix transform: " ~ debug.string(values, 0)
);
}
else
logpr(LOG_WARN, "Unknown transform type: '" ~ type ~ "'");
}
};
# ----------------------------------------------------------------------------
# Parse a path
# http://www.w3.org/TR/SVG/paths.html#PathData
# map svg commands OpenVG commands
var cmd_map = {
z: Path.VG_CLOSE_PATH,
m: Path.VG_MOVE_TO,
l: Path.VG_LINE_TO,
h: Path.VG_HLINE_TO,
v: Path.VG_VLINE_TO,
q: Path.VG_QUAD_TO,
c: Path.VG_CUBIC_TO,
t: Path.VG_SQUAD_TO,
s: Path.VG_SCUBIC_TO
};
var parsePath = func(path_data)
{
if( path_data == nil )
return;
var pos = 0;
var cmds = [];
var coords = [];
while(1)
{
# skip leading spaces
pos = path_data.find_first_not_of("\t\n ", pos);
if( pos < 0 )
break;
# get command (single character);
var cmd = substr(path_data, pos, 1);
pos += 1;
# and get all following arguments
# the '-' is kind of hard, it belongs to a number, might appear twice in
# one arg (e.g. -2e-3) and some SVG do not separate args starting with '-'
# so the '-' is the separator as well in this case.
# SVG samples (cut)
# 1: m 547.56916,962.17731 c 10e-6,25.66886 -20.80872,46.47759 -46.47758,46.47759 -25.66886,0 ...
# 2: M831,144.861c-0.236,0.087-0.423,0.255-0.629,0.39c-1.169,0.765-2.333,1.536-3.499,2.305 c-0.019,0.013-0.041, ...
var args = [];
#skip non-argument spaces and separator
pos = path_data.find_first_not_of(",\t\n ", pos);
var start_num = pos;
while(1)
{
pos = path_data.find_first_not_of(",\t\n ", pos);
if (pos < 0) break;
start_num = pos;
while (1) {
var chr1 = substr(path_data, pos, 1);
if (chr1 == "-")
pos = path_data.find_first_not_of("e.0123456789", pos + 1);
else
pos = path_data.find_first_not_of("e.0123456789", pos);
#check for e- (e.g. 42e-6)
if (pos > 0 and substr(path_data, pos - 1, 1) == "e"
and substr(path_data, pos, 1) == "-")
continue;
else
break;
}
if (start_num == pos) break;
append(args, substr( path_data,
start_num,
pos > 0 ? pos - start_num : nil ));
}
# now execute the command
var rel = string.islower(cmd[0]);
var cmd = string.lc(cmd);
if( cmd == 'a' )
{
for(var i = 0; i + 7 <= size(args); i += 7)
{
# SVG: (rx ry x-axis-rotation large-arc-flag sweep-flag x y)+
# OpenVG: rh,rv,rot,x0,y0
if( args[i + 3] )
var cmd_vg = args[i + 4] ? Path.VG_LCCWARC_TO : Path.VG_LCWARC_TO;
else
var cmd_vg = args[i + 4] ? Path.VG_SCCWARC_TO : Path.VG_SCWARC_TO;
append(cmds, rel ? cmd_vg + 1: cmd_vg);
append(coords, args[i],
args[i + 1],
args[i + 2],
args[i + 5],
args[i + 6] );
}
if( math.mod(size(args), 7) > 0 ) {
logpr(LOG_WARN, "Invalid number of coords for cmd 'a' ("~
size(args)~" mod 7 != 0)");
}
}
else
{
var cmd_vg = cmd_map[cmd];
if( cmd_vg == nil )
{
logpr(LOG_WARN, "command not found: '" ~ cmd ~ "'");
continue;
}
var num_coords = Path.num_coords[int(cmd_vg)];
if( num_coords == 0 )
append(cmds, cmd_vg);
else
{
for(var i = 0; i + num_coords <= size(args); i += num_coords)
{
append(cmds, rel ? cmd_vg + 1: cmd_vg);
for(var j = i; j < i + num_coords; j += 1)
append(coords, args[j]);
# If a moveto is followed by multiple pairs of coordinates, the
# subsequent pairs are treated as implicit lineto commands.
if( cmd == 'm' )
cmd_vg = cmd_map['l'];
}
if( math.mod(size(args), num_coords) > 0 )
logpr(LOG_WARN,"Invalid number of coords for cmd '" ~ cmd ~ "' ("
~size(args)~" mod "~num_coords~" != 0)"
);
}
}
}
stack[-1].setData(cmds, coords);
};
# ----------------------------------------------------------------------------
# Parse text styles (and apply them to the topmost element)
var parseTextStyles = func(style)
{
# http://www.w3.org/TR/SVG/text.html#TextAnchorProperty
var h_align = style["text-anchor"];
if( h_align != nil )
{
if( h_align == "end" )
h_align = "right";
else if( h_align == "middle" )
h_align = "center";
else # "start"
h_align = "left";
stack[-1].set("alignment", h_align ~ "-baseline");
}
# TODO vertical align
var fill = style['fill'];
if( fill != nil )
stack[-1].set("fill", fill);
var font_family = style["font-family"];
var font_weight = style["font-weight"];
var font_style = style["font-style"];
if( font_family != nil or font_weight != nil or font_style != nil )
stack[-1].set("font", font_mapper(font_family, font_weight, font_style, options));
var font_size = style["font-size"];
if( font_size != nil )
stack[-1].setDouble("character-size", evalCSSNum(font_size));
var line_height = style["line-height"];
if( line_height != nil )
stack[-1].setDouble("line-height", evalCSSNum(line_height));
}
# ----------------------------------------------------------------------------
# Parse a css style attribute
var parseStyle = func(style)
{
if( style == nil )
return {};
var styles = {};
foreach(var part; split(';', style))
{
if( !size(part = string.trim(part)) )
continue;
if( size(part = split(':',part)) != 2 )
continue;
var key = string.trim(part[0]);
if( !size(key) )
continue;
var value = string.trim(part[1]);
if( !size(value) )
continue;
styles[key] = value;
}
return styles;
}
# ----------------------------------------------------------------------------
# Parse a css color
var parseColor = func(s)
{
var color = [0, 0, 0];
if( s == nil )
return color;
if( size(s) == 7 and substr(s, 0, 1) == '#' )
{
return [ std.stoul(substr(s, 1, 2), 16) / 255,
std.stoul(substr(s, 3, 2), 16) / 255,
std.stoul(substr(s, 5, 2), 16) / 255 ];
}
return color;
};
# ----------------------------------------------------------------------------
# XML parsers element open callback
var start = func(name, attr)
{
level += 1;
if( skip )
return;
if( level == 1 )
{
if( name != 'svg' )
die("Not an svg file (root=" ~ name ~ ")");
else
return;
}
if( size(defs_stack) > 0 )
{
if( name == "mask" or name == "clipPath" )
{
append(defs_stack, {'type': name, 'id': attr['id']});
}
else if( name == "rect" )
{
foreach(var p; ["x", "y", "width", "height"])
defs_stack[-1][p] = evalCSSNum(attr[p]);
skip = level;
}
else
{
logpr(LOG_INFO, "Skipping unknown element in <defs>: <" ~ name ~ ">");
skip = level;
}
return;
}
var style = parseStyle(attr['style']);
var clip_id = attr['clip-path'] or attr['mask'];
if( clip_id != nil and clip_id != "none" )
{
if( clip_id.starts_with("url(#")
and clip_id[-1] == `)` )
clip_id = substr(clip_id, 5, size(clip_id) - 5 - 1);
cur_clip = clip_dict[clip_id];
if( cur_clip == nil )
logpr(LOG_WARN, "Clip not found: '" ~ clip_id ~ "'");
}
if( style['display'] == 'none' )
{
skip = level;
return;
}
else if( name == "g" )
{
pushElement('group', attr['id']);
}
else if( name == "text" )
{
text = {
"attr": attr,
"style": style,
"text": ""
};
tspans = [];
return;
}
else if( name == "tspan" )
{
append(tspans, {
"attr": attr,
"style": style,
"text": ""
});
return;
}
else if( name == "path" or name == "rect" or name == "circle" or name == "ellipse")
{
pushElement('path', attr['id']);
if( name == "rect" )
{
var width = evalCSSNum(attr['width']);
var height = evalCSSNum(attr['height']);
var x = evalCSSNum(attr['x']);
var y = evalCSSNum(attr['y']);
var rx = attr['rx'];
var ry = attr['ry'];
if( ry == nil )
ry = rx;
else if( rx == nil )
rx = ry;
var cfg = {};
if( rx != nil )
cfg["border-radius"] = [evalCSSNum(rx), evalCSSNum(ry)];
stack[-1].rect(x, y, width, height, cfg);
}
if (name == "circle") {
var cx = evalCSSNum(attr['cx']);
var cy = evalCSSNum(attr['cy']);
var r = evalCSSNum(attr['r']);
stack[-1].circle(r, cx, cy);
}
if (name == "ellipse") {
var cx = evalCSSNum(attr['cx']);
var cy = evalCSSNum(attr['cy']);
var rx = evalCSSNum(attr['rx']);
var ry = evalCSSNum(attr['ry']);
stack[-1].ellipse(rx, ry, cx, cy);
}
if (name == "path") {
parsePath(attr['d']);
}
var fill = style['fill'];
if( fill != nil )
stack[-1].set('fill', fill);
var fill_opacity = style['fill-opacity'];
if( fill_opacity != nil)
stack[-1].setDouble('fill-opacity', fill_opacity);
var stroke = style['stroke'];
if( stroke != nil )
stack[-1].set('stroke', stroke);
var stroke_opacity = style['stroke-opacity'];
if( stroke_opacity != nil)
stack[-1].setDouble('stroke-opacity', stroke_opacity);
var w = style['stroke-width'];
stack[-1].setStrokeLineWidth( w != nil ? evalCSSNum(w) : 1 );
var linecap = style['stroke-linecap'];
if( linecap != nil )
stack[-1].setStrokeLineCap(style['stroke-linecap']);
var linejoin = style['stroke-linejoin'];
if( linejoin != nil )
stack[-1].setStrokeLineJoin(style['stroke-linejoin']);
# http://www.w3.org/TR/SVG/painting.html#StrokeDasharrayProperty
var dash = style['stroke-dasharray'];
if( dash and size(dash) > 3 )
# at least 2 comma separated values...
stack[-1].setStrokeDashArray(split(',', dash));
} #end path/rect/ellipse/circle
else if( name == "use" )
{
var ref = attr["xlink:href"];
if( ref == nil or size(ref) < 2 or ref[0] != `#` )
return logpr(LOG_WARN, "Invalid or missing href: '" ~ ref ~ "'");
var el_src = id_dict[ substr(ref, 1) ];
if( el_src == nil )
return logpr(LOG_WARN, "Reference to unknown element '" ~ ref ~ "'");
# Create new element and copy sub branch from source node
pushElement(el_src._node.getName(), attr['id']);
props.copy(el_src._node, stack[-1]._node);
# copying also overrides the id so we need to set it again
stack[-1]._node.getNode("id").setValue(attr['id']);
}
else if( name == "defs" )
{
append(defs_stack, "defs");
return;
}
else if (name == "image" and options["parse_images"])
{
var ref = attr["xlink:href"];
# ref must not be missing and shall not contain Windows path separator
# find("\\") is correct, backslash is control character and must be escaped
# by adding another backslash - otherwise parse error anywhere below
if (ref == nil or find("\\", ref) > -1)
{
return logpr(LOG_WARN, "Invalid or missing href in image tag: '" ~ ref ~ "'");
}
if (substr(ref, 0, 5) == "data:") {
return logpr(LOG_WARN, "Unsupported embedded image");
}
elsif (substr(ref, 0, 5) != "file:") {
# absolute paths seem to start with "file:"
# prepend relative paths with the path of SVG file and hope the image is there
# file access limitations apply
ref = io.dirname(path) ~ ref;
}
pushElement("image", attr["id"]);
if (attr["x"] != nil and attr["y"] != nil) {
stack[-1].createTransform().setTranslation(attr["x"], attr["y"]);
}
if (attr["width"] != nil and attr["height"] != nil) {
stack[-1].setSize(attr["width"], attr["height"]);
}
stack[-1].setFile(ref);
}
else
{
logpr(LOG_INFO, "Skipping unknown element '" ~ name ~ "'");
skip = level;
return;
}
parseTransform(attr['transform']);
var cx = attr['inkscape:transform-center-x'];
if( cx != nil and cx != 0 )
stack[-1].setDouble("center-offset-x", evalCSSNum(cx));
var cy = attr['inkscape:transform-center-y'];
if( cy != nil and cy != 0 )
stack[-1].setDouble("center-offset-y", -evalCSSNum(cy));
};
# XML parsers element close callback
var end = func(name)
{
level -= 1;
if( skip )
{
if( level < skip )
skip = 0;
return;
}
if( size(defs_stack) > 0 )
{
if( name != "defs" )
{
var type = defs_stack[-1]['type'];
if( type == "mask" or type == "clipPath" )
clip_dict[defs_stack[-1]['id']] = defs_stack[-1];
}
pop(defs_stack);
return;
}
if( size(close_stack) and (level + 1) == close_stack[-1] )
popElement();
if( name == "text" )
{
# Inkscape/SVG text is a bit complicated. If we only got a single tspan
# or text without tspan we create just a single canvas.Text, otherwise
# we create a canvas.Group with a canvas.Text as child for each tspan.
# We need to take care to apply the transform attribute of the text
# element to the correct canvas element, and also correctly inherit
# the style properties.
var character_size = 24;
if( size(tspans) > 1 )
{
pushElement('group', text.attr['id']);
parseTextStyles(text.style);
parseTransform(text.attr['transform']);
character_size = stack[-1].get("character-size", character_size);
}
# Helper for getting first number in space separated list of numbers.
var first_num = func(str)
{
if( str == nil )
return 0;
var end = str.find_first_of(" \n\t");
if( end < 0 )
return str;
else
return substr(str, 0, end);
}
var line = 0;
foreach(var tspan; tspans)
{
# Always take first number and ignore individual character placment
var x = first_num(tspan.attr['x'] or text.attr['x']);
var y = first_num(tspan.attr['y'] or text.attr['y']);
# Sometimes Inkscape forgets writing x and y coordinates and instead
# just indicates a multiline text with sodipodi:role="line".
if( tspan.attr['y'] == nil and tspan.attr['sodipodi:role'] == "line" )
# TODO should we combine multiple lines into a single text separated
# with newline characters?
y += line
* stack[-1].get("line-height", 1.25)
* stack[-1].get("character-size", character_size);
# Use id of text element with single tspan child, fall back to id of
# tspan if text has no id.
var id = text.attr['id'];
if( id == nil or size(tspans) > 1 )
id = tspan.attr['id'];
pushElement('text', id);
stack[-1].setText(tspan.text);
if( x != 0 or y != 0 )
stack[-1].createTransform().setTranslation(x, y);
if( size(tspans) == 1 )
{
parseTextStyles(text.style);
parseTransform(text.attr['transform']);
}
parseTextStyles(tspan.style);
popElement();
line += 1;
}
if( size(tspans) > 1 )
popElement();
text = nil;
tspans = nil;
}
}; #end()
# XML parsers element data callback
var data = func(data)
{
if( skip )
return;
if( size(data) and tspans != nil )
{
if( size(tspans) == 0 )
# If no tspan is found use text element itself
append(tspans, text);
# If text contains xml entities it gets split at each entity. So let's
# glue it back into a single text...
tspans[-1]["text"] ~= data;
}
};
call(func parsexml(path, start, end, data), nil, var err = []);
if( size(err) )
{
logpr(LOG_ALERT, "parse XML failed");
debug.printerror(err);
return 0;
}
return 1;
}
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