1 files changed, 323 insertions, 0 deletions

diff --git a/src/display/canvas-text.cpp b/src/display/canvas-text.cpp
new file mode 100644
index 0000000..e725a1f
--- /dev/null
+++ b/src/display/canvas-text.cpp
@@ -0,0 +1,323 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Canvas text
+ *
+ * Authors:
+ *   Lauris Kaplinski <lauris@kaplinski.com>
+ *   Maximilian Albert <maximilian.albert@gmail.com>
+ *   Jon A. Cruz <jon@joncruz.org>
+ *
+ * Copyright (C) 2000-2002 Lauris Kaplinski
+ * Copyright (C) 2008 Maximilian Albert
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include <sstream>
+#include <cstring>
+
+#include "sp-canvas-util.h"
+#include "canvas-text.h"
+#include "display/cairo-utils.h"
+#include "desktop.h"
+#include "display/sp-canvas.h"
+
+static void sp_canvastext_destroy(SPCanvasItem *object);
+
+static void sp_canvastext_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags);
+static void sp_canvastext_render (SPCanvasItem *item, SPCanvasBuf *buf);
+
+G_DEFINE_TYPE(SPCanvasText, sp_canvastext, SP_TYPE_CANVAS_ITEM);
+
+static void sp_canvastext_class_init(SPCanvasTextClass *klass)
+{
+    SPCanvasItemClass *item_class = SP_CANVAS_ITEM_CLASS(klass);
+
+    item_class->destroy = sp_canvastext_destroy;
+    item_class->update = sp_canvastext_update;
+    item_class->render = sp_canvastext_render;
+}
+
+static void
+sp_canvastext_init (SPCanvasText *canvastext)
+{
+    canvastext->anchor_position = TEXT_ANCHOR_CENTER;
+    canvastext->anchor_pos_x_manual = 0;
+    canvastext->anchor_pos_y_manual = 0;
+    canvastext->anchor_offset_x = 0;
+    canvastext->anchor_offset_y = 0;
+    canvastext->rgba = 0x33337fff;
+    canvastext->rgba_stroke = 0xffffffff;
+    canvastext->rgba_background = 0x0000007f;
+    canvastext->background = false;
+    canvastext->s[Geom::X] = canvastext->s[Geom::Y] = 0.0;
+    canvastext->affine = Geom::identity();
+    canvastext->fontsize = 10.0;
+    canvastext->item = nullptr;
+    canvastext->desktop = nullptr;
+    canvastext->text = nullptr;
+    canvastext->outline = false;
+    canvastext->background = false;
+    canvastext->border = 3; // must be a constant, and not proportional to any width, height, or fontsize to allow alignment with other text boxes
+}
+
+static void sp_canvastext_destroy(SPCanvasItem *object)
+{
+    g_return_if_fail (object != nullptr);
+    g_return_if_fail (SP_IS_CANVASTEXT (object));
+
+    SPCanvasText *canvastext = SP_CANVASTEXT (object);
+
+    g_free(canvastext->text);
+    canvastext->text = nullptr;
+    canvastext->item = nullptr;
+
+    if (SP_CANVAS_ITEM_CLASS(sp_canvastext_parent_class)->destroy)
+        SP_CANVAS_ITEM_CLASS(sp_canvastext_parent_class)->destroy(object);
+}
+
+static void
+sp_canvastext_render (SPCanvasItem *item, SPCanvasBuf *buf)
+{
+    SPCanvasText *cl = SP_CANVASTEXT (item);
+
+    if (!buf->ct)
+        return;
+
+    cairo_select_font_face(buf->ct, "sans-serif", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
+    cairo_set_font_size(buf->ct, cl->fontsize);
+
+    if (cl->background){
+        cairo_text_extents_t extents;
+        cairo_text_extents(buf->ct, cl->text, &extents);
+
+        cairo_rectangle(buf->ct, item->x1 - buf->rect.left(),
+                                 item->y1 - buf->rect.top(),
+                                 item->x2 - item->x1,
+                                 item->y2 - item->y1);
+
+        ink_cairo_set_source_rgba32(buf->ct, cl->rgba_background);
+        cairo_fill(buf->ct);
+    }
+
+    Geom::Point s = cl->s * cl->affine;
+    double offsetx = s[Geom::X] - cl->anchor_offset_x - buf->rect.left();
+    double offsety = s[Geom::Y] - cl->anchor_offset_y - buf->rect.top();
+
+    cairo_move_to(buf->ct, round(offsetx), round(offsety));
+    cairo_text_path(buf->ct, cl->text);
+
+    if (cl->outline){
+        ink_cairo_set_source_rgba32(buf->ct, cl->rgba_stroke);
+        cairo_set_line_width (buf->ct, 2.0);
+        cairo_stroke_preserve(buf->ct);
+    }
+    ink_cairo_set_source_rgba32(buf->ct, cl->rgba);
+    cairo_fill(buf->ct);
+}
+
+static void
+sp_canvastext_update (SPCanvasItem *item, Geom::Affine const &affine, unsigned int flags)
+{
+    SPCanvasText *cl = SP_CANVASTEXT (item);
+
+    item->canvas->requestRedraw((int)item->x1, (int)item->y1, (int)item->x2, (int)item->y2);
+
+    if (SP_CANVAS_ITEM_CLASS(sp_canvastext_parent_class)->update)
+        SP_CANVAS_ITEM_CLASS(sp_canvastext_parent_class)->update(item, affine, flags);
+
+    sp_canvas_item_reset_bounds (item);
+
+    cl->affine = affine;
+
+    Geom::Point s = cl->s * affine;
+    // Point s specifies the position of the anchor, which is at the bounding box of the text itself (i.e. not at the border of the filled background rectangle)
+    // The relative position of the anchor can be set using e.g. anchor_position = TEXT_ANCHOR_LEFT
+
+    // Set up a temporary cairo_t to measure the text extents; it would be better to compute this in the render()
+    // method but update() seems to be called before so we don't have the information available when we need it
+    cairo_surface_t *tmp_surface = cairo_image_surface_create(CAIRO_FORMAT_ARGB32, 1, 1);
+    cairo_t* tmp_buf = cairo_create(tmp_surface);
+
+    cairo_select_font_face(tmp_buf, "sans-serif", CAIRO_FONT_SLANT_NORMAL, CAIRO_FONT_WEIGHT_NORMAL);
+    cairo_set_font_size(tmp_buf, cl->fontsize);
+    cairo_text_extents_t extents;
+    cairo_text_extents(tmp_buf, cl->text, &extents);
+    double border = cl->border;
+
+    item->x1 = s[Geom::X] + extents.x_bearing - border;
+    item->y1 = s[Geom::Y] + extents.y_bearing - border;
+    item->x2 = item->x1 + extents.width + 2*border;
+    item->y2 = item->y1 + extents.height + 2*border;
+
+    /* FROM: http://lists.cairographics.org/archives/cairo-bugs/2009-March/003014.html
+      - Glyph surfaces: In most font rendering systems, glyph surfaces
+        have an origin at (0,0) and a bounding box that is typically
+        represented as (x_bearing,y_bearing,width,height).  Depending on
+        which way y progresses in the system, y_bearing may typically be
+        negative (for systems similar to cairo, with origin at top left),
+        or be positive (in systems like PDF with origin at bottom left).
+        No matter which is the case, it is important to note that
+        (x_bearing,y_bearing) is the coordinates of top-left of the glyph
+        relative to the glyph origin.  That is, for example:
+
+        Scaled-glyph space:
+
+          (x_bearing,y_bearing) <-- negative numbers
+             +----------------+
+             |      .         |
+             |      .         |
+             |......(0,0) <---|-- glyph origin
+             |                |
+             |                |
+             +----------------+
+                      (width+x_bearing,height+y_bearing)
+
+        Note the similarity of the origin to the device space.  That is
+        exactly how we use the device_offset to represent scaled glyphs:
+        to use the device-space origin as the glyph origin.
+    */
+
+    // adjust update region according to anchor shift
+
+
+    switch (cl->anchor_position){
+        case TEXT_ANCHOR_LEFT:
+            cl->anchor_offset_x = 0;
+            cl->anchor_offset_y = -extents.height/2;
+            break;
+        case TEXT_ANCHOR_RIGHT:
+            cl->anchor_offset_x = extents.width;
+            cl->anchor_offset_y = -extents.height/2;
+            break;
+        case TEXT_ANCHOR_BOTTOM:
+            cl->anchor_offset_x = extents.width/2;
+            cl->anchor_offset_y = 0;
+            break;
+        case TEXT_ANCHOR_TOP:
+            cl->anchor_offset_x = extents.width/2;
+            cl->anchor_offset_y = -extents.height;
+            break;
+        case TEXT_ANCHOR_ZERO:
+            cl->anchor_offset_x = 0;
+            cl->anchor_offset_y = 0;
+            break;
+        case TEXT_ANCHOR_MANUAL:
+            cl->anchor_offset_x = (1 + cl->anchor_pos_x_manual) * extents.width/2;
+            cl->anchor_offset_y = -(1 + cl->anchor_pos_y_manual) * extents.height/2;
+            break;
+        case TEXT_ANCHOR_CENTER:
+        default:
+            cl->anchor_offset_x = extents.width/2;
+            cl->anchor_offset_y = -extents.height/2;
+            break;
+    }
+
+    cl->anchor_offset_x += extents.x_bearing;
+    cl->anchor_offset_y += extents.height + extents.y_bearing;
+
+    item->x1 -= cl->anchor_offset_x;
+    item->x2 -= cl->anchor_offset_x;
+    item->y1 -= cl->anchor_offset_y;
+    item->y2 -= cl->anchor_offset_y;
+
+    item->canvas->requestRedraw((int)item->x1, (int)item->y1, (int)item->x2, (int)item->y2);
+}
+
+SPCanvasText *sp_canvastext_new(SPCanvasGroup *parent, SPDesktop *desktop, Geom::Point pos, gchar const *new_text)
+{
+    // Pos specifies the position of the anchor, which is at the bounding box of the text itself (i.e. not at the border of the filled background rectangle)
+    // The relative position of the anchor can be set using e.g. anchor_position = TEXT_ANCHOR_LEFT
+    SPCanvasItem *item = sp_canvas_item_new(parent, SP_TYPE_CANVASTEXT, nullptr);
+
+    SPCanvasText *ct = SP_CANVASTEXT(item);
+
+    ct->desktop = desktop;
+
+    ct->s = pos;
+    g_free(ct->text);
+    ct->text = g_strdup(new_text);
+
+    return ct;
+}
+
+
+void
+sp_canvastext_set_rgba32 (SPCanvasText *ct, guint32 rgba, guint32 rgba_stroke)
+{
+    g_return_if_fail (ct != nullptr);
+    g_return_if_fail (SP_IS_CANVASTEXT (ct));
+
+    if (rgba != ct->rgba || rgba_stroke != ct->rgba_stroke) {
+        ct->rgba = rgba;
+        ct->rgba_stroke = rgba_stroke;
+        SPCanvasItem *item = SP_CANVAS_ITEM (ct);
+        sp_canvas_item_request_update( item );
+    }
+}
+
+#define EPSILON 1e-6
+#define DIFFER(a,b) (fabs ((a) - (b)) > EPSILON)
+
+void
+sp_canvastext_set_coords (SPCanvasText *ct, gdouble x0, gdouble y0)
+{
+    sp_canvastext_set_coords(ct, Geom::Point(x0, y0));
+}
+
+void
+sp_canvastext_set_coords (SPCanvasText *ct, const Geom::Point start)
+{
+    g_return_if_fail (ct && ct->desktop);
+    g_return_if_fail (SP_IS_CANVASTEXT (ct));
+    
+    Geom::Point pos = ct->desktop->doc2dt(start);
+
+    if (DIFFER (pos[0], ct->s[Geom::X]) || DIFFER (pos[1], ct->s[Geom::Y])) {
+        ct->s[Geom::X] = pos[0];
+        ct->s[Geom::Y] = pos[1];
+        sp_canvas_item_request_update (SP_CANVAS_ITEM (ct));
+    }
+}
+
+void
+sp_canvastext_set_text (SPCanvasText *ct, gchar const * new_text)
+{
+    g_free (ct->text);
+    ct->text = g_strdup(new_text);
+    sp_canvas_item_request_update (SP_CANVAS_ITEM (ct));
+}
+
+void
+sp_canvastext_set_number_as_text (SPCanvasText *ct, int num)
+{
+    std::ostringstream number;
+    number << num;
+    sp_canvastext_set_text(ct, number.str().c_str());
+}
+
+void
+sp_canvastext_set_fontsize (SPCanvasText *ct, double size)
+{
+    ct->fontsize = size;
+}
+
+void
+sp_canvastext_set_anchor_manually (SPCanvasText *ct, double anchor_x, double anchor_y)
+{
+    ct->anchor_pos_x_manual = anchor_x;
+    ct->anchor_pos_y_manual = anchor_y;
+    ct->anchor_position = TEXT_ANCHOR_MANUAL;
+}
+
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :