aboutsummaryrefslogtreecommitdiffstats
path: root/src/libgamma-facade.c
diff options
context:
space:
mode:
Diffstat (limited to 'src/libgamma-facade.c')
-rw-r--r--src/libgamma-facade.c132
1 files changed, 132 insertions, 0 deletions
diff --git a/src/libgamma-facade.c b/src/libgamma-facade.c
index 07dfd9b..81c6d8a 100644
--- a/src/libgamma-facade.c
+++ b/src/libgamma-facade.c
@@ -56,6 +56,7 @@
# endif
#endif
+#include <unistd.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
@@ -74,6 +75,137 @@
#endif
+
+#ifdef HAVE_GAMMA_METHODS
+# ifdef HAVE_GAMMA_METHOD_LINUX_DRM
+/**
+ * Test whether a file descriptor refers to a VT
+ *
+ * @param fd The file descriptor
+ * @return Whether the file descriptor refers to a VT
+ */
+static int libgamma_is_vt_proper(int fd)
+{
+ char buf[32];
+ char digit0;
+
+ if (ttyname_r(fd, buf, sizeof(buf) / sizeof(char)))
+ return 0;
+
+ if (strstr(buf, "/dev/tty") != buf)
+ return 0;
+
+ digit0 = buf[strlen("/dev/tty")];
+ return ('1' <= digit0) && (digit0 <= '9');
+}
+# endif
+
+
+/**
+ * Test the availability of an adjustment method
+ *
+ * @param method The adjustment method
+ * @param operation Allowed values:
+ * 0: Pass if the environment suggests it will work but is not fake.
+ * 1: Pass if the environment suggests it will work.
+ * 2: Pass if real and not fake.
+ * 3: Pass if real.
+ * 4: Always pass.
+ * Other values invoke undefined behaviour.
+ * @return Whether the test passed
+ */
+static int libgamma_list_method_test(int method, int operation)
+{
+ libgamma_method_capabilities_t caps;
+ libgamma_method_capabilities(&caps, method);
+
+ switch (operation)
+ {
+ case 0: /* Methods that the environment suggests will work, excluding fake. */
+ if (caps.fake)
+ return 0;
+ /* Fall through. */
+
+ case 1: /* Methods that the environment suggests will work, including fake. */
+ if (caps.real == 0)
+ return 0;
+#ifdef HAVE_GAMMA_METHOD_LINUX_DRM
+ if (method == GAMMA_METHOD_LINUX_DRM)
+ return libgamma_is_vt_proper(STDIN_FILENO) ||
+ libgamma_is_vt_proper(STDOUT_FILENO) ||
+ libgamma_is_vt_proper(STDERR_FILENO);
+#endif
+#ifdef HAVE_GAMMA_METHOD_DUMMY
+ if (method == GAMMA_METHOD_DUMMY)
+ return 0;
+#endif
+ return caps.default_site_known;
+
+ case 2: /* All real non-fake methods. */
+ return caps.real && (caps.fake == 0);
+
+ case 3: /* All real methods. */
+ return caps.real;
+
+ default: /* All methods. */
+ return 1;
+ }
+}
+#endif
+
+
+/**
+ * List available adjustment methods by their order of preference based on the environment
+ *
+ * @param methods Output array of methods, should be able to hold `GAMMA_METHOD_COUNT` elements
+ * @param operation Allowed values:
+ * 0: Methods that the environment suggests will work, excluding fake.
+ * 1: Methods that the environment suggests will work, including fake.
+ * 2: All real non-fake methods.
+ * 3: All real methods.
+ * 4: All methods.
+ * Other values invoke undefined behaviour.
+ * @return The number of element that have been stored in `methods`
+ */
+size_t libgamma_list_methods(int* methods, int operation)
+{
+#ifdef HAVE_NO_GAMMA_METHODS
+ (void) methods;
+ (void) operation;
+ return 0;
+#else
+ size_t n = 0;
+
+#ifdef HAVE_GAMMA_METHOD_RANDR
+ if (libgamma_list_method_test(GAMMA_METHOD_RANDR, operation))
+ methods[n++] = GAMMA_METHOD_RANDR;
+#endif
+#ifdef HAVE_GAMMA_METHOD_VIDMODE
+ if (libgamma_list_method_test(GAMMA_METHOD_VIDMODE, operation))
+ methods[n++] = GAMMA_METHOD_VIDMODE;
+#endif
+#ifdef HAVE_GAMMA_METHOD_LINUX_DRM
+ if (libgamma_list_method_test(GAMMA_METHOD_LINUX_DRM, operation))
+ methods[n++] = GAMMA_METHOD_LINUX_DRM;
+#endif
+#ifdef HAVE_GAMMA_METHOD_W32_GDI
+ if (libgamma_list_method_test(GAMMA_METHOD_W32_GDI, operation))
+ methods[n++] = GAMMA_METHOD_W32_GDI;
+#endif
+#ifdef HAVE_GAMMA_METHOD_QUARTZ_CORE_GRAPHICS
+ if (libgamma_list_method_test(GAMMA_METHOD_QUARTZ_CORE_GRAPHICS, operation))
+ methods[n++] = GAMMA_METHOD_QUARTZ_CORE_GRAPHICS;
+#endif
+#ifdef HAVE_GAMMA_METHOD_DUMMY
+ if (libgamma_list_method_test(GAMMA_METHOD_DUMMY, operation))
+ methods[n++] = GAMMA_METHOD_DUMMY;
+#endif
+
+ return n;
+#endif
+}
+
+
/**
* Return the capabilities of an adjustment method
*