test: Add a very basic test to exercise BLT text drawing

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

test/Makefile.am

@@ -1,6 +1,7 @@
 stress_TESTS = \
 	basic-fillrect \
 	basic-rectangle \
+	basic-string \
 	basic-copyarea \
 	basic-copyarea-size \
 	basic-putimage \

test/basic-string.c

@@ -0,0 +1,102 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <X11/Xutil.h> /* for XDestroyImage */
+
+#include "test.h"
+
+static void draw_string(struct test_display *t, Drawable d, uint8_t alu,
+			int x, int y, uint32_t fg, uint32_t bg, int s, int fill)
+{
+	const char *strings[] = {
+		"Hello",
+		"World",
+		"Cairo's twin is Giza",
+	};
+	XGCValues val;
+	GC gc;
+
+	val.function = alu;
+	val.foreground = fg;
+	val.background = bg;
+
+	gc = XCreateGC(t->dpy, d, GCForeground | GCBackground | GCFunction, &val);
+	if (fill)
+		XDrawImageString(t->dpy, d, gc, x, y, strings[s%3], strlen(strings[s%3]));
+	else
+		XDrawString(t->dpy, d, gc, x, y, strings[s%3], strlen(strings[s%3]));
+	XFreeGC(t->dpy, gc);
+}
+
+static void clear(struct test_display *dpy, struct test_target *tt)
+{
+	XRenderColor render_color = {0};
+	XRenderFillRectangle(dpy->dpy, PictOpClear, tt->picture, &render_color,
+			     0, 0, tt->width, tt->height);
+}
+
+static void string_tests(struct test *t, int reps, int sets, enum target target)
+{
+	struct test_target real, ref;
+	int r, s;
+
+	printf("Testing general (%s): ", test_target_name(target));
+	fflush(stdout);
+
+	test_target_create_render(&t->real, target, &real);
+	clear(&t->real, &real);
+
+	test_target_create_render(&t->ref, target, &ref);
+	clear(&t->ref, &ref);
+
+	for (s = 0; s < sets; s++) {
+		for (r = 0; r < reps; r++) {
+			int x = rand() % (2*real.width) - real.width;
+			int y = rand() % (2*real.height) - real.height;
+			uint8_t alu = rand() % (GXset + 1);
+			uint32_t fg = rand();
+			uint32_t bg = rand();
+			int str = rand();
+			int fill = rand() & 1;
+
+			draw_string(&t->real, real.draw, alu, x, y, fg, bg, str, fill);
+			draw_string(&t->ref, ref.draw, alu, x, y, fg, bg, str, fill);
+		}
+
+		test_compare(t,
+			     real.draw, real.format,
+			     ref.draw, ref.format,
+			     0, 0, real.width, real.height,
+			     "");
+	}
+
+	printf("passed [%d iterations x %d]\n", reps, sets);
+
+	test_target_destroy_render(&t->real, &real);
+	test_target_destroy_render(&t->ref, &ref);
+}
+
+int main(int argc, char **argv)
+{
+	struct test test;
+	int i;
+
+	test_init(&test, argc, argv);
+
+	for (i = 0; i <= DEFAULT_ITERATIONS; i++) {
+		int reps = 1 << i;
+		int sets = 1 << (12 - i);
+		enum target t;
+
+		if (sets < 2)
+			sets = 2;
+
+		for (t = TARGET_FIRST; t <= TARGET_LAST; t++) {
+			string_tests(&test, reps, sets, t);
+		}
+	}
+
+	return 0;
+}