[PATCH 1/2] kdrive: add support to +X+Y syntax in -screen option parsing

[Laércio de Sousa]

This patch enhances current -screen option parsing for kdrive-based
applications. It can parse strings like
<WIDTH>x<HEIGHT>+<XOFFSET>+<YOFFSET>, storing X and Y offsets
in KdScreenInfo instances.

It will allow e.g. proper Xephyr window placement for multiseat
purposes.
---
 hw/kdrive/src/kdrive.c | 33 ++++++++++++++++++++++++++++-----
 hw/kdrive/src/kdrive.h |  2 ++
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/hw/kdrive/src/kdrive.c b/hw/kdrive/src/kdrive.c
index 8eb8cd0..8a3d119 100644
--- a/hw/kdrive/src/kdrive.c
+++ b/hw/kdrive/src/kdrive.c
@@ -284,7 +284,7 @@ KdSubRotation(Rotation a, Rotation b)
 void
 KdParseScreen(KdScreenInfo * screen, const char *arg)
 {
-    char delim;
+    char delim, saved_delim;
     char save[1024];
     int i;
     int pixels, mm;
@@ -293,6 +293,8 @@ KdParseScreen(KdScreenInfo * screen, const char *arg)
     screen->softCursor = kdSoftCursor;
     screen->origin = kdOrigin;
     screen->randr = RR_Rotate_0;
+    screen->x = 0;
+    screen->y = 0;
     screen->width = 0;
     screen->height = 0;
     screen->width_mm = 0;
@@ -306,7 +308,7 @@ KdParseScreen(KdScreenInfo * screen, const char *arg)
         return;
 
     for (i = 0; i < 2; i++) {
-        arg = KdParseFindNext(arg, "x/@XY", save, &delim);
+        arg = KdParseFindNext(arg, "x/+- at XY", save, &delim);
         if (!save[0])
             return;
 
@@ -314,7 +316,7 @@ KdParseScreen(KdScreenInfo * screen, const char *arg)
         mm = 0;
 
         if (delim == '/') {
-            arg = KdParseFindNext(arg, "x at XY", save, &delim);
+            arg = KdParseFindNext(arg, "x+- at XY", save, &delim);
             if (!save[0])
                 return;
             mm = atoi(save);
@@ -328,7 +330,8 @@ KdParseScreen(KdScreenInfo * screen, const char *arg)
             screen->height = pixels;
             screen->height_mm = mm;
         }
-        if (delim != 'x' && delim != '@' && delim != 'X' && delim != 'Y' &&
+        if (delim != 'x' && delim != '+' && delim != '-' &&
+            delim != '@' && delim != 'X' && delim != 'Y' &&
             (delim != '\0' || i == 0))
             return;
     }
@@ -339,6 +342,26 @@ KdParseScreen(KdScreenInfo * screen, const char *arg)
     kdSoftCursor = FALSE;
     kdSubpixelOrder = SubPixelUnknown;
 
+    if (delim == '+' || delim == '-') {
+        saved_delim = delim;
+        arg = KdParseFindNext(arg, "+- at xXY", save, &delim);
+        if (save[0]) {
+            if (saved_delim == '-')
+                screen->x = -atoi(save);
+            else
+                screen->x = atoi(save);
+        }
+    }
+    if (delim == '+' || delim == '-') {
+        saved_delim = delim;
+        arg = KdParseFindNext(arg, "@xXY", save, &delim);
+        if (save[0]) {
+            if (saved_delim == '-')
+                screen->y = -atoi(save);
+            else
+                screen->y = atoi(save);
+        }
+    }
     if (delim == '@') {
         arg = KdParseFindNext(arg, "xXY", save, &delim);
         if (save[0]) {
@@ -418,7 +441,7 @@ KdUseMsg(void)
 {
     ErrorF("\nTinyX Device Dependent Usage:\n");
     ErrorF
-        ("-screen WIDTH[/WIDTHMM]xHEIGHT[/HEIGHTMM][@ROTATION][X][Y][xDEPTH/BPP[xFREQ]]  Specify screen characteristics\n");
+        ("-screen WIDTH[/WIDTHMM]xHEIGHT[/HEIGHTMM][+-XOFFSET][+-YOFFSET][@ROTATION][X][Y][xDEPTH/BPP[xFREQ]]  Specify screen characteristics\n");
     ErrorF
         ("-rgba rgb/bgr/vrgb/vbgr/none   Specify subpixel ordering for LCD panels\n");
     ErrorF
diff --git a/hw/kdrive/src/kdrive.h b/hw/kdrive/src/kdrive.h
index bec75cb..89b29fe 100644
--- a/hw/kdrive/src/kdrive.h
+++ b/hw/kdrive/src/kdrive.h
@@ -89,6 +89,8 @@ typedef struct _KdScreenInfo {
     ScreenPtr pScreen;
     void *driver;
     Rotation randr;             /* rotation and reflection */
+    int x;
+    int y;
     int width;
     int height;
     int rate;
-- 
1.8.4.5