[librsvg] image.rs: Move NodeImage over to Rust. Yay!

[Federico Mena Quintero <federico src gnome org>]

commit 6c66c98e2d529372db180b32d1a5a7199547174e
Author: Federico Mena Quintero <federico gnome org>
Date:   Mon Sep 25 19:14:23 2017 -0500

    image.rs: Move NodeImage over to Rust.  Yay!

 Makefile.am       |    1 +
 rsvg-base.c       |    4 +-
 rsvg-image.c      |  213 -----------------------------------------------------
 rsvg-image.h      |   55 --------------
 rust/src/image.rs |  126 +++++++++++++++++++++++++++++++
 rust/src/lib.rs   |    5 +
 6 files changed, 134 insertions(+), 270 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index 7203bcf..3525902 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -79,6 +79,7 @@ RUST_SOURCES =                                        \
        rust/src/error.rs                       \
        rust/src/gradient.rs                    \
        rust/src/handle.rs                      \
+       rust/src/image.rs                       \
        rust/src/length.rs                      \
        rust/src/lib.rs                         \
        rust/src/marker.rs                      \
diff --git a/rsvg-base.c b/rsvg-base.c
index e6a6192..392344d 100644
--- a/rsvg-base.c
+++ b/rsvg-base.c
@@ -316,7 +316,7 @@ static const NodeCreator node_creators[] = {
     /* "glyph",              TRUE,  */
     /* "glyphRef",           TRUE,  */
     /* "hkern",              FALSE, */
-    { "image",               TRUE,  rsvg_new_image },
+    { "image",               TRUE,  rsvg_node_image_new },
     { "line",                TRUE,  rsvg_node_line_new },
     { "linearGradient",      TRUE,  rsvg_node_linear_gradient_new },
     { "marker",              TRUE,  rsvg_node_marker_new },
@@ -336,7 +336,7 @@ static const NodeCreator node_creators[] = {
     { "stop",                TRUE,  rsvg_node_stop_new },
     /* "style",              FALSE, */
     { "subImage",            FALSE, rsvg_node_group_new },
-    { "subImageRef",         FALSE, rsvg_new_image },
+    { "subImageRef",         FALSE, rsvg_node_image_new },
     { "svg",                 TRUE,  rsvg_node_svg_new },
     { "switch",              TRUE,  rsvg_node_switch_new },
     { "symbol",              TRUE,  rsvg_node_symbol_new },
diff --git a/rust/src/image.rs b/rust/src/image.rs
new file mode 100644
index 0000000..6b415e4
--- /dev/null
+++ b/rust/src/image.rs
@@ -0,0 +1,126 @@
+use libc;
+use cairo;
+use cairo_sys;
+use glib;
+use glib::translate::*;
+use glib_sys;
+use std::cell::{Cell, RefCell};
+use std::ptr;
+
+use drawing_ctx;
+use drawing_ctx::RsvgDrawingCtx;
+
+use aspect_ratio::*;
+use handle::RsvgHandle;
+use length::*;
+use node::*;
+use property_bag;
+use property_bag::RsvgPropertyBag;
+
+struct NodeImage {
+    aspect:  Cell<AspectRatio>,
+    x:       Cell<RsvgLength>,
+    y:       Cell<RsvgLength>,
+    w:       Cell<RsvgLength>,
+    h:       Cell<RsvgLength>,
+    surface: RefCell<Option<cairo::ImageSurface>>
+}
+
+impl NodeImage {
+    fn new () -> NodeImage {
+        NodeImage {
+            aspect:  Cell::new (AspectRatio::default ()),
+            x:       Cell::new (RsvgLength::default ()),
+            y:       Cell::new (RsvgLength::default ()),
+            w:       Cell::new (RsvgLength::default ()),
+            h:       Cell::new (RsvgLength::default ()),
+            surface: RefCell::new (None)
+        }
+    }
+}
+
+impl NodeTrait for NodeImage {
+    fn set_atts (&self, _: &RsvgNode, handle: *const RsvgHandle, pbag: *const RsvgPropertyBag) -> NodeResult 
{
+        self.x.set (property_bag::parse_or_default (pbag, "x", LengthDir::Horizontal, None)?);
+        self.y.set (property_bag::parse_or_default (pbag, "y", LengthDir::Vertical, None)?);
+        self.w.set (property_bag::parse_or_default (pbag, "width", LengthDir::Horizontal,
+                                                    Some(RsvgLength::check_nonnegative))?);
+        self.h.set (property_bag::parse_or_default (pbag, "height", LengthDir::Vertical,
+                                                    Some(RsvgLength::check_nonnegative))?);
+        self.aspect.set (property_bag::parse_or_default (pbag, "preserveAspectRatio", (), None)?);
+
+        let mut href = property_bag::lookup (pbag, "xlink:href");
+
+        if href.is_none() {
+            // "path" is used by some older adobe illustrator versions
+            href = property_bag::lookup (pbag, "path");
+        }
+
+        if let Some(href) = href {
+            extern "C" { fn rsvg_cairo_surface_new_from_href
+                         (handle: *const RsvgHandle,
+                          href:   *const libc::c_char,
+                          error:  *mut *mut glib_sys::GError) -> *mut cairo_sys::cairo_surface_t;
+            }
+
+            let mut error = ptr::null_mut();
+
+            let raw_surface = unsafe { rsvg_cairo_surface_new_from_href (handle,
+                                                                         href.to_glib_none().0,
+                                                                         &mut error) };
+            if !raw_surface.is_null() {
+                *self.surface.borrow_mut() = Some(unsafe { cairo::ImageSurface::from_raw_full 
(raw_surface).unwrap() });
+            } else {
+                let _: glib::Error = unsafe { from_glib_full(error) }; // FIXME: we should note that the 
image couldn't be loaded
+            }
+        }
+
+        Ok (())
+    }
+
+    fn draw (&self, node: &RsvgNode, draw_ctx: *const RsvgDrawingCtx, dominate: i32) {
+        if let Some(ref surface) = *self.surface.borrow() {
+            let x = self.x.get().normalize(draw_ctx);
+            let y = self.y.get().normalize(draw_ctx);
+            let w = self.w.get().normalize(draw_ctx);
+            let h = self.h.get().normalize(draw_ctx);
+
+            let state = node.get_state();
+
+            drawing_ctx::state_reinherit_top(draw_ctx, state, dominate);
+            drawing_ctx::push_discrete_layer(draw_ctx);
+
+            let aspect = self.aspect.get();
+
+            if !drawing_ctx::state_is_overflow(state) {
+                match aspect.align {
+                    Align::Aligned { align: _,
+                                     fit: FitMode::Slice } => {
+                        drawing_ctx::add_clipping_rect(draw_ctx, x, y, w, h);
+                    },
+
+                    _ => ()
+                }
+            }
+
+            let (x, y, w, h) = aspect.compute (surface.get_width() as f64,
+                                               surface.get_height() as f64,
+                                               x, y, w, h);
+
+            drawing_ctx::render_surface(draw_ctx, &surface, x, y, w, h);
+
+            drawing_ctx::pop_discrete_layer(draw_ctx);
+        }
+    }
+
+    fn get_c_impl (&self) -> *const RsvgCNodeImpl {
+        unreachable! ();
+    }
+}
+
+#[no_mangle]
+pub extern fn rsvg_node_image_new (_: *const libc::c_char, raw_parent: *const RsvgNode) -> *const RsvgNode {
+    boxed_node_new (NodeType::Image,
+                    raw_parent,
+                    Box::new (NodeImage::new ()))
+}
diff --git a/rust/src/lib.rs b/rust/src/lib.rs
index 3bb6dbe..2533e22 100644
--- a/rust/src/lib.rs
+++ b/rust/src/lib.rs
@@ -50,6 +50,10 @@ pub use length::{
     rsvg_length_hand_normalize,
 };
 
+pub use image::{
+    rsvg_node_image_new,
+};
+
 pub use marker::{
     rsvg_node_marker_new,
 };
@@ -132,6 +136,7 @@ mod drawing_ctx;
 mod error;
 mod gradient;
 mod handle;
+mod image;
 mod length;
 mod marker;
 mod node;