Fix some issues with line breaks in canvas objects.

These bugs were exposed by comment objects, now that explicit line
breaks in comments are actually working.

- Text paste turned each newline in the pasted text into two consecutive
  newlines. This is actually the expected behavior of insertText
  according to the specs, as newlines are interpreted as paragraph
  breaks, not line breaks. So we now insert lines one by one, and
  manually add the line breaks instead.

- Empty lines weren't rendered correctly by text_to_tspans, as empty
  tspans are just ignored in the layout algorithm. So we now use
  absolute instead of relative baseline offsets there.

pd/nw/pd_canvas.js

@@ -717,8 +717,23 @@ var canvas_events = (function() {
             },
             text_paste: function(evt) {
                 evt.preventDefault();
-                document.execCommand("insertText", false,
-                    evt.clipboardData.getData("text"));
+                var text = evt.clipboardData.getData("text");
+                // ag: We need to insert each line individually here, with
+                // line breaks in between. Otherwise the behavior of
+                // "insertText" is to insert a *paragraph* break between
+                // lines, so that we get two newlines for each newline in the
+                // input. (Who thought that this was a good design? There's
+                // probably a reason why this WebKit API is deprecated, but
+                // since there's no replacement for it, we have to use it.)
+                // Also note that we skip the line break at the end of the
+                // paste buffer, since it will be stripped off on the C side
+                // during object creation anyway.
+                var lines = text.split("\n");
+                for (var i = 0; i < lines.length; i++) {
+                    document.execCommand("insertText", false, lines[i]);
+                    if (i < lines.length-1)
+                        document.execCommand("insertLineBreak", false);
+                }
                 grow_svg_for_element(textbox());
             },
             floating_text_click: function(evt) {

pd/nw/pdgui.js

@@ -3794,13 +3794,16 @@ function text_to_tspans(cid, svg_text, text) {
     len = lines.length;
     // Get fontsize (minus the trailing "px")
     fontsize = svg_text.getAttribute("font-size").slice(0, -2);
+    var dy = text_line_height_kludge(+fontsize, "gui");
     for (i = 0; i < len; i++) {
+        // ag: We need to specify absolute y offsets for the baseline
+        // positions here. Relative dy offsets, which were used previously,
+        // don't advance the y position if no glyphs are rendered, so empty
+        // lines aren't rendered correctly.
         tspan = create_item(cid, "tspan", {
-            dy: i == 0 ? 0 : text_line_height_kludge(+fontsize, "gui") + "px",
+            y: ((i+1)*dy) + "px",
             x: 0
         });
-        // tspan needs at least one char so that empty lines are preserved
-        if (lines[i] == "") lines[i] = " ";
         // find a way to abstract away the canvas array and the DOM here
         text_node = patchwin[cid].window.document
                     .createTextNode(lines[i]);

pd/src/g_rtext.c

@@ -312,17 +312,6 @@ static void rtext_senditup(t_rtext *x, int action, int *widthp, int *heightp,
                 ncolumns = foundit_c;
             nlines++;
         }
-        // append new line in case we end our input with an \n
-        // suppressed at the end of a comment (backport from pd-l2ork)
-        int iscomment = pd_class(&x->x_text->te_pd) == text_class &&
-            x->x_text->te_type == T_TEXT;
-        if (!iscomment && x_bufsize_c > 0 && (x->x_buf[x->x_bufsize - 1] == '\n' || x->x_buf[x->x_bufsize - 1] == '\v'))
-        {
-            nlines++;
-            tempbuf[outchars_b++] = '\n';
-            //tempbuf[outchars_b] = '\0';
-            //outchars_b++;
-        }
         if (!reportedindex)
             *indexp = outchars_b;
         if (nlines < 1) nlines = 1;
@@ -653,8 +642,7 @@ void rtext_activate(t_rtext *x, int state)
        null terminated. If this becomes a problem we can revisit
        it later */
     tmpbuf = t_getbytes(x->x_bufsize + 1);
-    sprintf(tmpbuf, "%.*s", (int)x->x_bufsize, x->x_buf);
-    /* in case x_bufsize is 0... */
+    snprintf(tmpbuf, x->x_bufsize+1, "%s", x->x_buf);
     tmpbuf[x->x_bufsize] = '\0';
     gui_vmess("gui_textarea", "xssiiiisiiiiiii",
         canvas,