Fix 998529, mono (invert) cursors not visible on a black background, by doing
simple edge detection on the cursor (this is done once when the cursor
is changed and then cached, cursors are 32x32 generally) and thus having
a cursor with contrast on both dark and light backgrounds.
When (if) GDK gets invert cursor support (wayland?) then we can just use
the cursor as is. Until then X doesn't provide any way I see of solving
this otherwise. The end result was tested with the I beam cursor that
the original bug was referring to (run putty on a windows 7 vm) and
looks ok to me.
---
gtk/channel-cursor.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 75 insertions(+), 3 deletions(-)
diff --git a/gtk/channel-cursor.c b/gtk/channel-cursor.c
index d1d2c34..322afd9 100644
--- a/gtk/channel-cursor.c
+++ b/gtk/channel-cursor.c
@@ -246,19 +246,90 @@ static void do_emit_main_context(GObject *object, int signum, gpointer params)
/* ------------------------------------------------------------------ */
-static void mono_cursor(display_cursor *cursor, const guint8 *data)
+#ifdef DEBUG_CURSOR
+static void print_cursor(display_cursor *cursor, const guint8 *data)
{
+ int x, y, bpl;
const guint8 *xor, *and;
+
+ bpl = (cursor->hdr.width + 7) / 8;
+ and = data;
+ xor = and + bpl * cursor->hdr.height;
+
+ printf("data (%d x %d):\n", cursor->hdr.width, cursor->hdr.height);
+ for (y = 0 ; y < cursor->hdr.height; ++y) {
+ for (x = 0 ; x < cursor->hdr.width / 8; x++) {
+ printf("%02X", and[x]);
+ }
+ and += bpl;
+ printf("\n");
+ }
+ printf("xor:\n");
+ for (y = 0 ; y < cursor->hdr.height; ++y) {
+ for (x = 0 ; x < cursor->hdr.width / 8; ++x) {
+ printf("%02X", xor[x]);
+ }
+ xor += bpl;
+ printf("\n");
+ }
+}
+#endif
+
+static bool cursor_xor_pixel(const guint8 *xor, int bpl, int x, int y)
+{
+ return (xor[bpl * y + (x / 8)] & (0x80 >> (x % 8))) > 0;
+}
+
+static guint8 cursor_is_xor_edge(display_cursor *cursor, const guint8 *xor, int bpl, int x, int y)
+{
+ if (x == 0 || x == cursor->hdr.width -1 || y == 0 || y == cursor->hdr.height - 1) {
+ return 0;
+ }
+#define P(x, y) cursor_xor_pixel(xor, bpl, x, y)
+ return !P(x, y) && (P(x - 1, y + 1) || P(x, y + 1) || P(x + 1, y + 1) ||
+ P(x - 1, y) || P(x + 1, y) ||
+ P(x - 1, y - 1) || P(x, y - 1) || P(x + 1, y - 1));
+#undef P
+}
+
+static bool cursor_is_and_ones(display_cursor *cursor, const guint8 *data)
+{
+ int x, y, bpl;
+
+ bpl = (cursor->hdr.width + 7) / 8;
+ for (y = 0 ; y < cursor->hdr.height; ++y) {
+ for (x = 0 ; x < cursor->hdr.width / 8; ++x) {
+ if (data[x] != 0xff) {
+ return false;
+ }
+ }
+ data += bpl;
+ }
+ return true;
+}
+
+static void mono_cursor(SpiceChannel *channel, display_cursor *cursor, const guint8 *data)
+{
+ const guint8 *xor, *xor_base, *and;
guint8 *dest;
int bpl, x, y, bit;
+ bool and_ones = cursor_is_and_ones(cursor, data);
bpl = (cursor->hdr.width + 7) / 8;
and = data;
- xor = and + bpl * cursor->hdr.height;
+ xor_base = xor = and + bpl * cursor->hdr.height;
dest = (uint8_t *)cursor->data;
+#ifdef DEBUG_CURSOR
+ print_cursor(cursor, data);
+#endif
for (y = 0; y < cursor->hdr.height; y++) {
bit = 0x80;
for (x = 0; x < cursor->hdr.width; x++, dest += 4) {
+ if (cursor_is_xor_edge(cursor, xor_base, bpl, x, y) && and_ones) {
+ dest[0] = dest[1] = dest[2] = 0x00;
+ dest[3] = 0xff;
+ goto next_bit;
+ }
if (and[x/8] & bit) {
if (xor[x/8] & bit) {
/*
@@ -301,6 +372,7 @@ static void mono_cursor(display_cursor *cursor, const guint8 *data)
dest[3] = 0xff;
}
}
+ next_bit:
bit >>= 1;
if (bit == 0) {
bit = 0x80;
@@ -395,7 +467,7 @@ static display_cursor *set_cursor(SpiceChannel *channel, SpiceCursor *scursor)
switch (hdr->type) {
case SPICE_CURSOR_TYPE_MONO:
- mono_cursor(cursor, data);
+ mono_cursor(channel, cursor, data);
break;
case SPICE_CURSOR_TYPE_ALPHA:
memcpy(cursor->data, data, size);