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// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
use svgdom::{
Length,
};
use super::prelude::*;
pub fn resolve_font_size(doc: &Document, opt: &Options) {
_resolve_font_size(&doc.root(), opt);
}
pub fn _resolve_font_size(parent: &Node, opt: &Options) {
for (_, mut node) in parent.children().svg() {
// We have to resolve `font-size` for all elements
// and not only for 'text content' based,
// because it will be used during `em`/`ex` units conversion.
//
// https://www.w3.org/TR/2008/REC-CSS2-20080411/fonts.html#propdef-font-size
let font_size = match node.attributes().get(AId::FontSize) {
Some(v) => {
v.value.clone()
}
None => {
// If not set - lookup in parent nodes or use default.
let mut len = node.find_attribute(AId::FontSize)
.unwrap_or(Length::new_number(opt.font_size));
// If `font-size` is not set and the parent one is `em` or `ex`
// then the current `'`font-size`'` is `1em` or `2ex` respectively.
// This way do not introduce an additional scaling.
//
// Example:
// <g font-size='12'>
// <g font-size='3em'>
// <g>
//
// The values are '12', '3em' and 'None'.
// And the expected results are '12', '36' and '36'.
// But if we simply copy the '3em' to the 'None' place we will
// get '12', '36' and '108'.
if len.unit == Unit::Em {
len.num = 1.0;
} else if len.unit == Unit::Ex {
// The same coefficient as in convert_units::convert.
len.num = 2.0;
}
AValue::Length(len)
}
};
let font_size = match font_size {
AValue::Length(len) => {
if len.unit == Unit::Percent {
process_percent_font_size(parent, len, opt)
} else {
len
}
}
AValue::String(ref name) => {
process_named_font_size(parent, name, &font_size, opt)
}
_ => {
warn!("Invalid 'font-size' value: {}.", font_size);
Length::new_number(opt.font_size)
}
};
// We have to mark this attribute as invisible,
// otherwise it will break the `use` resolving.
if !node.has_attribute(AId::FontSize) {
node.set_attribute(("resolved-font-size", 1));
}
node.set_attribute((AId::FontSize, font_size));
if node.has_children() {
_resolve_font_size(&node, opt);
}
}
}
// If `font-size` has percent units that it's value
// is relative to the parent node `font-size`.
fn process_percent_font_size(parent: &Node, len: Length, opt: &Options) -> Length {
if parent.is_root() {
Length::new_number(opt.font_size)
} else {
let parent_len = parent.find_attribute(AId::FontSize)
.unwrap_or(Length::new_number(opt.font_size));
let n = len.num * parent_len.num * 0.01;
Length::new_number(n)
}
}
fn process_named_font_size(
parent: &Node,
name: &str,
font_size: &AValue,
opt: &Options,
) -> Length {
let factor = match name {
"xx-small" => -3,
"x-small" => -2,
"small" => -1,
"medium" => 0,
"large" => 1,
"x-large" => 2,
"xx-large" => 3,
"smaller" => -1,
"larger" => 1,
_ => {
warn!("Invalid 'font-size' value: {}.", font_size);
0
}
};
let parent_len = parent.find_attribute(AId::FontSize)
.unwrap_or(Length::new_number(opt.font_size));
// 'On a computer screen a scaling factor of 1.2
// is suggested between adjacent indexes'
let n = parent_len.num * 1.2f64.powi(factor);
Length::new_number(n)
}