librsvg source for verification 2026-05-22

pango-examples/Cargo.toml

@@ -0,0 +1,32 @@
+[package]
+name = "pango-examples"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+cairo-rs = { version = "0.21", features = ["v1_16", "png"] }
+pango = { version = "0.21", features = ["v1_54"] }
+pangocairo = "0.21"
+
+[build-dependencies]
+system-deps = "7.0.0"
+
+[package.metadata.system-deps]
+cairo = "1.18"
+cairo-gobject = "1.18"
+cairo-png = "1.18"
+pangocairo = "1.50"
+
+[[bin]]
+name = "example_1_trivial"
+path = "src/example_1_trivial.rs"
+
+[[bin]]
+name = "example_2_attributes"
+path = "src/example_2_attributes.rs"
+
+[[bin]]
+name = "example_3_glyphs"
+path = "src/example_3_glyphs.rs"
+
+[workspace]

pango-examples/build.rs

@@ -0,0 +1,10 @@
+fn probe_system_deps() {
+    if let Err(e) = system_deps::Config::new().probe() {
+        eprintln!("{e}");
+        std::process::exit(1);
+    }
+}
+
+fn main() {
+    probe_system_deps();
+}

pango-examples/src/example_1_trivial.rs

@@ -0,0 +1,36 @@
+use cairo;
+use pango;
+use pango::prelude::*;
+use pangocairo;
+
+use std::fs::File;
+
+fn main() {
+    // Create a font map, in this case the default one which uses the system's fonts.
+    let font_map = pangocairo::FontMap::default();
+
+    // Create a pango context.  We set the resolution to 72 dots-per-inch so that the sizes we specify
+    // later will be pixel sizes, instead of point sizes (Pango's API takes points).
+    let pango_context = font_map.create_context();
+    pangocairo::functions::context_set_resolution(&pango_context, 72.0);
+
+    // Create a Cairo image surface for our output
+    let surface = cairo::ImageSurface::create(cairo::Format::ARgb32, 400, 400).unwrap();
+    let cr = cairo::Context::new(&surface).unwrap();
+    cr.set_source_rgba(1.0, 1.0, 1.0, 1.0);
+    cr.paint().unwrap();
+
+    // Note how this uses all the defaults in Pango.  The text will probably
+    // be set in a sans-serif font, 10 pixels tall or so.
+    let layout = pango::Layout::new(&pango_context);
+    layout.set_text("Hello world!");
+
+    // Set the paint color to black; that's what pangocairo will use.
+    cr.set_source_rgba(0.0, 0.0, 0.0, 1.0);
+    cr.move_to(100.0, 100.0);
+    pangocairo::functions::show_layout(&cr, &layout);
+
+    // Write a PNG file from the surface
+    let mut output = File::create("example_1_trivial.png").unwrap();
+    surface.write_to_png(&mut output).unwrap();
+}

pango-examples/src/example_2_attributes.rs

@@ -0,0 +1,75 @@
+use cairo;
+use pango;
+use pango::prelude::*;
+use pangocairo;
+
+use std::fs::File;
+
+fn main() {
+    // Create a font map, in this case the default one which uses the system's fonts.
+    let font_map = pangocairo::FontMap::default();
+
+    // Create a pango context.  We set the resolution to 72 dots-per-inch so that the sizes we specify
+    // later will be pixel sizes, instead of point sizes (Pango's API takes points).
+    let pango_context = font_map.create_context();
+    pangocairo::functions::context_set_resolution(&pango_context, 72.0);
+
+    // Create a Cairo image surface for our output
+    let surface = cairo::ImageSurface::create(cairo::Format::ARgb32, 800, 400).unwrap();
+    let cr = cairo::Context::new(&surface).unwrap();
+    cr.set_source_rgba(1.0, 1.0, 1.0, 1.0);
+    cr.paint().unwrap();
+
+    // Note how this uses all the defaults in Pango.  The text will probably
+    // be set in a sans-serif font, 10 pixels tall or so.
+    let layout = pango::Layout::new(&pango_context);
+
+    let text = "Hello böld world in itálics!";
+    layout.set_text(&text);
+
+    // Create an attribute list and an array of attributes to put in it
+    let attr_list = pango::AttrList::new();
+
+    // Font description and style; this spans the whole string
+    let mut font_desc = pango::FontDescription::new();
+    font_desc.set_family("Sans");
+    font_desc.set_size(40 * pango::SCALE); // sizes in Pango are scaled by this factor
+    let mut attr = pango::AttrFontDesc::new(&font_desc).upcast();
+    attr.set_start_index(0);
+    attr.set_end_index(text.len() as u32); // in bytes
+    attr_list.insert(attr);
+
+    // Make the word bold; note how we use byte offsets
+    let mut font_desc = pango::FontDescription::new();
+    font_desc.set_weight(pango::Weight::Bold);
+    let mut attr = pango::AttrFontDesc::new(&font_desc).upcast();
+    attr.set_start_index(text.find("böld").unwrap() as u32);
+    attr.set_end_index((text.find("böld").unwrap() + "böld".len()) as u32);
+    attr_list.insert(attr);
+
+    // Make the two words italics; same as the previous one
+    let mut font_desc = pango::FontDescription::new();
+    font_desc.set_style(pango::Style::Italic);
+    let mut attr = pango::AttrFontDesc::new(&font_desc).upcast();
+    attr.set_start_index(text.find("in itálics").unwrap() as u32);
+    attr.set_end_index((text.find("in itálics").unwrap() + "in itálics".len()) as u32);
+    attr_list.insert(attr);
+
+    // Also make "in italics" red
+    let mut attr = pango::AttrColor::new_foreground(0xffff, 0x0000, 0x0000);
+    attr.set_start_index(text.find("in itálics").unwrap() as u32);
+    attr.set_end_index((text.find("in itálics").unwrap() + "in itálics".len()) as u32);
+    attr_list.insert(attr);
+
+    // Finally, set the attribute list on the layout
+    layout.set_attributes(Some(&attr_list));
+
+    // Set the paint color to black; that's what pangocairo will use.
+    cr.set_source_rgba(0.0, 0.0, 0.0, 1.0);
+    cr.move_to(100.0, 100.0);
+    pangocairo::functions::show_layout(&cr, &layout);
+
+    // Write a PNG file from the surface
+    let mut output = File::create("example_2_attributes.png").unwrap();
+    surface.write_to_png(&mut output).unwrap();
+}

pango-examples/src/example_3_glyphs.rs

@@ -0,0 +1,129 @@
+use cairo;
+use pango;
+use pango::prelude::*;
+use pangocairo;
+
+use std::fs::File;
+
+fn main() {
+    // Create a font map, in this case the default one which uses the system's fonts.
+    let font_map = pangocairo::FontMap::default();
+
+    // Create a pango context.  We set the resolution to 72 dots-per-inch so that the sizes we specify
+    // later will be pixel sizes, instead of point sizes (Pango's API takes points).
+    let pango_context = font_map.create_context();
+    pangocairo::functions::context_set_resolution(&pango_context, 72.0);
+
+    // Create a Cairo image surface for our output
+    let surface = cairo::ImageSurface::create(cairo::Format::ARgb32, 800, 400).unwrap();
+    let cr = cairo::Context::new(&surface).unwrap();
+    cr.set_source_rgba(1.0, 1.0, 1.0, 1.0);
+    cr.paint().unwrap();
+
+    let layout = pango::Layout::new(&pango_context);
+    fill_layout(&layout);
+
+    // We will iterate the layout by hand
+    // line
+    //   runs
+    //     clusters
+
+    let mut iter = layout.iter();
+    while let Some(_line) = iter.line_readonly() {
+        while let Some(run) = iter.run_readonly() {
+            let item = run.item();
+            let glyph_string = run.glyph_string();
+
+            println!(
+                "item.offfset: {}, item.char_offset: {}",
+                item.offset(),
+                item.char_offset(),
+            );
+
+            println!("glyph_string num_glyphs: {}", glyph_string.num_glyphs(),);
+
+            for glyph_info in glyph_string.glyph_info() {
+                let geometry = glyph_info.geometry();
+
+                println!(
+                    "    glyph {} width={} x_offset={} y_offset={}",
+                    glyph_info.glyph(),
+                    geometry.width(),
+                    geometry.x_offset(),
+                    geometry.y_offset(),
+                );
+            }
+
+            for glyph_info in glyph_string.glyph_info() {
+                let geometry = glyph_info.geometry();
+
+                println!(
+                    "    glyph {} width={} x_offset={} y_offset={}",
+                    glyph_info.glyph(),
+                    geometry.width(),
+                    geometry.x_offset(),
+                    geometry.y_offset(),
+                );
+            }
+
+            if !iter.next_run() {
+                break;
+            }
+        }
+
+        if !iter.next_line() {
+            break;
+        }
+    }
+
+    // Set the paint color to black; that's what pangocairo will use.
+    cr.set_source_rgba(0.0, 0.0, 0.0, 1.0);
+    cr.move_to(100.0, 100.0);
+    pangocairo::functions::show_layout(&cr, &layout);
+
+    // Write a PNG file from the surface
+    let mut output = File::create("example_3_glyphs.png").unwrap();
+    surface.write_to_png(&mut output).unwrap();
+}
+
+fn fill_layout(layout: &pango::Layout) {
+    let text = "Hello böld world in itálics!";
+    layout.set_text(&text);
+
+    // Create an attribute list and an array of attributes to put in it
+    let attr_list = pango::AttrList::new();
+
+    // Font description and style; this spans the whole string
+    let mut font_desc = pango::FontDescription::new();
+    font_desc.set_family("Sans");
+    font_desc.set_size(40 * pango::SCALE); // sizes in Pango are scaled by this factor
+    let mut attr = pango::AttrFontDesc::new(&font_desc).upcast();
+    attr.set_start_index(0);
+    attr.set_end_index(text.len() as u32); // in bytes
+    attr_list.insert(attr);
+
+    // Make the word bold; note how we use byte offsets
+    let mut font_desc = pango::FontDescription::new();
+    font_desc.set_weight(pango::Weight::Bold);
+    let mut attr = pango::AttrFontDesc::new(&font_desc).upcast();
+    attr.set_start_index(text.find("böld").unwrap() as u32);
+    attr.set_end_index((text.find("böld").unwrap() + "böld".len()) as u32);
+    attr_list.insert(attr);
+
+    // Make the two words italics; same as the previous one
+    let mut font_desc = pango::FontDescription::new();
+    font_desc.set_style(pango::Style::Italic);
+    let mut attr = pango::AttrFontDesc::new(&font_desc).upcast();
+    attr.set_start_index(text.find("in itálics").unwrap() as u32);
+    attr.set_end_index((text.find("in itálics").unwrap() + "in itálics".len()) as u32);
+    attr_list.insert(attr);
+
+    // Also make "in italics" red
+    let mut attr = pango::AttrColor::new_foreground(0xffff, 0x0000, 0x0000);
+    attr.set_start_index(text.find("in itálics").unwrap() as u32);
+    attr.set_end_index((text.find("in itálics").unwrap() + "in itálics".len()) as u32);
+    attr_list.insert(attr);
+
+    // Finally, set the attribute list on the layout
+    layout.set_attributes(Some(&attr_list));
+}