Fix some issues with resampling drawings

The X scale/offset was being used for both X and Y coordinates.

Only non-negative integers were supported. xy-VSFilter and libass both
now support non-integer coordinates, and negative coordinates have of
course always been valid. Resampled coordinates are now rounded to
eighth-pixels rather than whole pixels.

aegisub/src/resolution_resampler.cpp

@@ -21,9 +21,11 @@
 #include "ass_dialogue.h"
 #include "ass_file.h"
 #include "ass_style.h"
+#include "utils.h"
 
 #include <libaegisub/of_type_adaptor.h>
 #include <libaegisub/split.h>
+#include <libaegisub/util.h>
 
 #include <algorithm>
 #include <boost/algorithm/string/predicate.hpp>
@@ -44,14 +46,16 @@ namespace {
 		final.reserve(drawing.size());
 
 		for (auto const& cur : agi::Split(drawing, ' ')) {
-			if (std::all_of(begin(cur), end(cur), isdigit)) {
-				int val = boost::lexical_cast<int>(agi::str(cur));
+			double val;
+			if (agi::util::try_parse(agi::str(cur), &val)) {
 				if (is_x)
-					val = (int)((val + shift_x) * scale_x + .5);
+					val = (val + shift_x) * scale_x;
 				else
-					val = (int)((val + shift_y) * scale_y + .5);
-				final += std::to_string(val);
+					val = (val + shift_y) * scale_y;
+				val = int(val * 8 + .5) / 8.0; // round to eighth-pixels
+				final += float_to_string(val);
 				final += ' ';
+				is_x = !is_x;
 			}
 			else if (cur.size() == 1) {
 				char c = tolower(cur[0]);

aegisub/src/utils.cpp

@@ -86,6 +86,14 @@ wxString PrettySize(int bytes) {
 	return wxString::Format(fmt, size) + " " + suffix[i];
 }
 
+std::string float_to_string(double val) {
+	std::string s = str(boost::format("%.3f") % val);
+	size_t pos = s.find_last_not_of("0");
+	if (pos != s.find(".")) ++pos;
+	s.erase(begin(s) + pos, end(s));
+	return s;
+}
+
 void StatusTimeout(wxString const& msg, int ms) {
 	wxGetApp().frame->StatusTimeout(msg, ms);
 }

aegisub/src/utils.h

@@ -52,6 +52,8 @@ class wxWindow;
 
 wxString PrettySize(int bytes);
 
+std::string float_to_string(double val);
+
 void StatusTimeout(wxString const& msg, int ms = 10000);
 
 /// @brief Get the smallest power of two that is greater or equal to x

aegisub/src/vector2d.cpp

@@ -23,6 +23,8 @@
 
 #include "vector2d.h"
 
+#include "utils.h"
+
 #include <boost/format.hpp>
 #include <limits>
 
@@ -86,13 +88,6 @@ std::string Vector2D::DStr(char sep) const {
 	return str(boost::format("%d%c%d") % (int)x % sep % (int)y);
 }
 
-static std::string float_to_string(float val) {
-	std::string s = str(boost::format("%.3f") % val);
-	size_t pos = s.find_last_not_of("0");
-	if (pos != s.find(".")) ++pos;
-	return s.substr(0, pos);
-}
-
 std::string Vector2D::Str(char sep) const {
 	return float_to_string(x) + sep + float_to_string(y);
 }