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fix(renderer): Use proper font scaling based on DPI

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This tries to mimic the old renderer's behavior as closely as possible.
In the absence of any information, DPI is assumed to be 96x96. DPI can
be configured on a per-bar basis using the configuration key "dpi".

To use the DPI configuration from Xresources (if built with support),
one can specify the following in the bar config:

dpi = ${xrdb:Xft.dpi:96}
This commit is contained in:
Chase Geigle 2017-01-24 20:08:14 -06:00 committed by Michael Carlberg
parent 8d79b582ec
commit e7dc6b8bbb
2 changed files with 23 additions and 7 deletions
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14
include/cairo/font.hpp
View File

@ -30,7 +30,7 @@ namespace cairo {
virtual string name() const = 0;
virtual string file() const = 0;
virtual double offset() const = 0;
virtual double size() const = 0;
virtual double size(double dpi) const = 0;
virtual cairo_font_extents_t extents() = 0;
@ -54,10 +54,10 @@ namespace cairo {
*/
class font_fc : public font {
public:
explicit font_fc(cairo_t* cairo, FcPattern* pattern, double offset) : font(cairo, offset), m_pattern(pattern) {
explicit font_fc(cairo_t* cairo, FcPattern* pattern, double offset, double dpi_x, double dpi_y) : font(cairo, offset), m_pattern(pattern) {
cairo_matrix_t fm;
cairo_matrix_t ctm;
cairo_matrix_init_scale(&fm, size(), size());
cairo_matrix_init_scale(&fm, size(dpi_x), size(dpi_y));
cairo_get_matrix(m_cairo, &ctm);
auto fontface = cairo_ft_font_face_create_for_pattern(m_pattern);
@ -111,12 +111,14 @@ namespace cairo {
return m_offset;
}
double size() const override {
double size(double dpi) const override {
bool scalable;
double px;
property(FC_SCALABLE, &scalable);
if (scalable) {
// convert from pt to px using the provided dpi
property(FC_SIZE, &px);
px = static_cast<int>(px * dpi / 72.0 + 0.5);
} else {
property(FC_PIXEL_SIZE, &px);
px = static_cast<int>(px + 0.5);
@ -234,7 +236,7 @@ namespace cairo {
/**
* Match and create font from given fontconfig pattern
*/
decltype(auto) make_font(cairo_t* cairo, string&& fontname, double offset) {
decltype(auto) make_font(cairo_t* cairo, string&& fontname, double offset, double dpi_x, double dpi_y) {
static bool fc_init{false};
if (!fc_init && !(fc_init = FcInit())) {
throw application_error("Could not load fontconfig");
@ -263,7 +265,7 @@ namespace cairo {
FcPatternPrint(match);
#endif
return make_shared<font_fc>(cairo, match, offset);
return make_shared<font_fc>(cairo, match, offset, dpi_x, dpi_y);
}
}

16
src/components/renderer.cpp
View File

@ -121,6 +121,20 @@ renderer::renderer(
m_log.trace("renderer: Load fonts");
{
double dpi_x = 96, dpi_y = 96;
if (m_conf.has(m_conf.section(), "dpi")) {
try {
// dpi specified directly as a value
dpi_x = dpi_y = m_conf.get<double>("dpi");
} catch (const value_error&) {
// dpi to be comptued
auto screen = m_connection.screen();
dpi_x = screen->width_in_pixels * 25.4 / screen->width_in_millimeters;
dpi_y = screen->height_in_pixels * 25.4 / screen->height_in_millimeters;
}
}
m_log.trace("renderer: DPI is %.1fx%.1f", dpi_x, dpi_y);
auto fonts = m_conf.get_list<string>(m_conf.section(), "font", {});
if (fonts.empty()) {
m_log.warn("No fonts specified, using fallback font \"fixed\"");
@ -130,7 +144,7 @@ renderer::renderer(
auto fonts_loaded = false;
for (const auto& f : fonts) {
vector<string> fd{string_util::split(f, ';')};
auto font = cairo::make_font(*m_context, string(fd[0]), fd.size() > 1 ? std::atoi(fd[1].c_str()) : 0);
auto font = cairo::make_font(*m_context, string(fd[0]), fd.size() > 1 ? std::atoi(fd[1].c_str()) : 0, dpi_x, dpi_y);
m_log.info("Loaded font \"%s\" (name=%s, file=%s)", fd[0], font->name(), font->file());
*m_context << move(font);
fonts_loaded = true;