[librsvg: 3/6] drawing_ctx: move initial rect calculation to rust

[Federico Mena Quintero <federico src gnome org>]

commit 175374b7d20560dbddb46c660eaa24b8466e29d3
Author: Paolo Borelli <pborelli gnome org>
Date:   Sun May 13 18:53:33 2018 +0200

    drawing_ctx: move initial rect calculation to rust

 librsvg/rsvg-drawing-ctx.c        | 45 ++++++++-------------------------------
 rsvg_internals/src/drawing_ctx.rs | 29 +++++++++++++++++++++++++
 rsvg_internals/src/lib.rs         |  6 +++++-
 3 files changed, 43 insertions(+), 37 deletions(-)
---
diff --git a/librsvg/rsvg-drawing-ctx.c b/librsvg/rsvg-drawing-ctx.c
index 630227ff..02132cfb 100644
--- a/librsvg/rsvg-drawing-ctx.c
+++ b/librsvg/rsvg-drawing-ctx.c
@@ -52,6 +52,12 @@ void rsvg_cairo_add_clipping_rect (RsvgDrawingCtx *ctx,
                                    double w,
                                    double h);
 
+/* Implemented in rsvg_internals/src/draw.rs */
+G_GNUC_INTERNAL
+void rsvg_drawing_ctx_transformed_image_bounding_box (cairo_matrix_t *affine,
+                                                      double width, double height,
+                                                      double *x0, double *y0, double *x1, double *y1);
+
 static void
 rsvg_cairo_generate_mask (cairo_t * cr, RsvgNode *mask, RsvgDrawingCtx *ctx)
 {
@@ -255,39 +261,6 @@ rsvg_cairo_clip (RsvgDrawingCtx *ctx, RsvgNode *node_clip_path, RsvgBbox *bbox)
     cairo_clip (ctx->cr);
 }
 
-static void
-rsvg_cairo_transformed_image_bounding_box (cairo_matrix_t *affine,
-                                           double width, double height,
-                                           double *x0, double *y0, double *x1, double *y1)
-{
-    double x00 = 0, x01 = 0, x10 = width, x11 = width;
-    double y00 = 0, y01 = height, y10 = 0, y11 = height;
-    double t;
-
-    /* transform the four corners of the image */
-    cairo_matrix_transform_point (affine, &x00, &y00);
-    cairo_matrix_transform_point (affine, &x01, &y01);
-    cairo_matrix_transform_point (affine, &x10, &y10);
-    cairo_matrix_transform_point (affine, &x11, &y11);
-
-    /* find minimum and maximum coordinates */
-    t = x00  < x01 ? x00  : x01;
-    t = t < x10 ? t : x10;
-    *x0 = floor (t < x11 ? t : x11);
-
-    t = y00  < y01 ? y00  : y01;
-    t = t < y10 ? t : y10;
-    *y0 = floor (t < y11 ? t : y11);
-
-    t = x00  > x01 ? x00  : x01;
-    t = t > x10 ? t : x10;
-    *x1 = ceil (t > x11 ? t : x11);
-
-    t = y00  > y01 ? y00  : y01;
-    t = t > y10 ? t : y10;
-    *y1 = ceil (t > y11 ? t : y11);
-}
-
 RsvgDrawingCtx *
 rsvg_drawing_ctx_new (cairo_t *cr, RsvgHandle *handle)
 {
@@ -309,9 +282,9 @@ rsvg_drawing_ctx_new (cairo_t *cr, RsvgHandle *handle)
     /* find bounding box of image as transformed by the current cairo context
      * The size of this bounding box determines the size of the intermediate
      * surfaces allocated during drawing. */
-    rsvg_cairo_transformed_image_bounding_box (&affine,
-                                               data.width, data.height,
-                                               &bbx0, &bby0, &bbx1, &bby1);
+    rsvg_drawing_ctx_transformed_image_bounding_box (&affine,
+                                                     data.width, data.height,
+                                                     &bbx0, &bby0, &bbx1, &bby1);
 
     draw->initial_cr = cr;
     draw->cr = cr;
diff --git a/rsvg_internals/src/drawing_ctx.rs b/rsvg_internals/src/drawing_ctx.rs
index c30fd7ef..7edd9e69 100644
--- a/rsvg_internals/src/drawing_ctx.rs
+++ b/rsvg_internals/src/drawing_ctx.rs
@@ -11,6 +11,7 @@ use bbox::RsvgBbox;
 use length::LengthUnit;
 use node::NodeType;
 use node::RsvgNode;
+use rect;
 use state::{self, BaselineShift, FontSize, RsvgState, State};
 
 pub enum RsvgDrawingCtx {}
@@ -390,6 +391,34 @@ impl AcquiredNode {
     }
 }
 
+#[no_mangle]
+pub extern "C" fn rsvg_drawing_ctx_transformed_image_bounding_box(
+    affine: *const cairo::Matrix,
+    w: f64,
+    h: f64,
+    x0: *mut libc::c_double,
+    y0: *mut libc::c_double,
+    x1: *mut libc::c_double,
+    y1: *mut libc::c_double,
+) {
+    let affine = unsafe { &*affine };
+    let r = cairo::Rectangle {
+        x: 0.0,
+        y: 0.0,
+        width: w,
+        height: h,
+    };
+
+    let r_out = rect::transform(affine, &r);
+
+    unsafe {
+        *x0 = r_out.x.floor();
+        *y0 = r_out.y.floor();
+        *x1 = (r_out.x + r_out.width).ceil();
+        *y1 = (r_out.y + r_out.height).ceil();
+    }
+}
+
 #[no_mangle]
 pub extern "C" fn rsvg_drawing_ctx_state_push(draw_ctx: *mut RsvgDrawingCtx) {
     state_push(draw_ctx);
diff --git a/rsvg_internals/src/lib.rs b/rsvg_internals/src/lib.rs
index 5aa731a9..fc0334d0 100644
--- a/rsvg_internals/src/lib.rs
+++ b/rsvg_internals/src/lib.rs
@@ -33,7 +33,11 @@ pub use color::{rsvg_css_parse_color, ColorKind, ColorSpec};
 
 pub use draw::rsvg_cairo_add_clipping_rect;
 
-pub use drawing_ctx::{rsvg_drawing_ctx_state_pop, rsvg_drawing_ctx_state_push};
+pub use drawing_ctx::{
+    rsvg_drawing_ctx_state_pop,
+    rsvg_drawing_ctx_state_push,
+    rsvg_drawing_ctx_transformed_image_bounding_box,
+};
 
 pub use gradient::{rsvg_node_linear_gradient_new, rsvg_node_radial_gradient_new};