tests: change rgb_diff_stat printing

Seems it will be common to print all four min/max/avg sets of errors, so
move the printing code into a shared place.

While 0.0-1.0 is the natural range for color values, people are often
accustomed to working with 8-bit or even 10-bit pixel values. An error
of +/- 1 in 8-bit is more intuitive than +/- 0.004 in floating-point.
Hence 'scaling_bits' is added so the caller can determine the value
scaling. This will scale both the reported error numbers, and the
recorded error positions (rgb-tuples), so they are all comparable.

I'm happy to get rid of those two macros as well.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.com>

tests/color-icc-output-test.c

@@ -189,8 +189,6 @@ test_roundtrip(uint8_t r, uint8_t g, uint8_t b, cmsPipeline *pip,
 static void
 roundtrip_verification(cmsPipeline *DToB, cmsPipeline *BToD, float tolerance)
 {
-	const char *const chan_name[COLOR_CHAN_NUM] = { "r", "g", "b" };
-	unsigned i;
 	unsigned r, g, b;
 	struct rgb_diff_stat stat = {};
 	cmsPipeline *pip;
@@ -211,15 +209,7 @@ roundtrip_verification(cmsPipeline *DToB, cmsPipeline *BToD, float tolerance)
 
 	cmsPipelineFree(pip);
 
-	testlog("DToB->BToD roundtrip error statistics (%u samples):\n",
-		stat.two_norm.count);
-	for (i = 0; i < COLOR_CHAN_NUM; i++) {
-		testlog("  ch %s error:\n", chan_name[i]);
-		scalar_stat_print_rgb8bit(&stat.rgb[i]);
-	}
-	testlog("  Two-norm error:\n");
-	scalar_stat_print_rgb8bit(&stat.two_norm);
-
+	rgb_diff_stat_print(&stat, "DToB->BToD roundtrip", 8);
 	assert(stat.two_norm.max < tolerance);
 }
 

tests/color_util.c

@@ -396,17 +396,6 @@ scalar_stat_avg(const struct scalar_stat *stat)
 	return stat->sum / stat->count;
 }
 
-#define RGB888_FMT "(%3u, %3u, %3u)"
-#define RGB888_VAL(cf) (unsigned)round((cf).r * 255.0), (unsigned)round((cf).g * 255.0), (unsigned)round((cf).b * 255.0)
-
-void
-scalar_stat_print_rgb8bit(const struct scalar_stat *stat)
-{
-	testlog("    min %8.5f at " RGB888_FMT "\n", stat->min, RGB888_VAL(stat->min_pos));
-	testlog("    max %8.5f at " RGB888_FMT "\n", stat->max, RGB888_VAL(stat->max_pos));
-	testlog("    avg %8.5f\n", scalar_stat_avg(stat));
-}
-
 void
 scalar_stat_print_float(const struct scalar_stat *stat)
 {
@@ -415,6 +404,41 @@ scalar_stat_print_float(const struct scalar_stat *stat)
 	testlog("    avg %11.5g\n", scalar_stat_avg(stat));
 }
 
+static void
+print_stat_at_pos(const char *lim, double val, struct color_float pos, double scale)
+{
+	testlog("    %s %8.5f at rgb(%7.2f, %7.2f, %7.2f)\n",
+		lim, val * scale, pos.r * scale, pos.g * scale, pos.b * scale);
+}
+
+static void
+print_rgb_at_pos(const struct scalar_stat *stat, double scale)
+{
+	print_stat_at_pos("min", stat->min, stat->min_pos, scale);
+	print_stat_at_pos("max", stat->max, stat->max_pos, scale);
+	testlog("    avg %8.5f\n", scalar_stat_avg(stat) * scale);
+}
+
+void
+rgb_diff_stat_print(const struct rgb_diff_stat *stat,
+		    const char *title, unsigned scaling_bits)
+{
+	const char *const chan_name[COLOR_CHAN_NUM] = { "r", "g", "b" };
+	float scale = exp2f(scaling_bits) - 1.0f;
+	unsigned i;
+
+	assert(scaling_bits > 0);
+
+	testlog("%s error statistics, %u samples, value range 0.0 - %.1f:\n",
+		title, stat->two_norm.count, scale);
+	for (i = 0; i < COLOR_CHAN_NUM; i++) {
+		testlog("  ch %s (signed):\n", chan_name[i]);
+		print_rgb_at_pos(&stat->rgb[i], scale);
+	}
+	testlog("  rgb two-norm:\n");
+	print_rgb_at_pos(&stat->two_norm, scale);
+}
+
 void
 rgb_diff_stat_update(struct rgb_diff_stat *stat,
 		     struct color_float *ref, struct color_float *val)

tests/color_util.h

@@ -144,12 +144,13 @@ scalar_stat_update(struct scalar_stat *stat, double val, struct color_float *pos
 float
 scalar_stat_avg(const struct scalar_stat *stat);
 
-void
-scalar_stat_print_rgb8bit(const struct scalar_stat *stat);
-
 void
 scalar_stat_print_float(const struct scalar_stat *stat);
 
 void
 rgb_diff_stat_update(struct rgb_diff_stat *stat,
 		     struct color_float *ref, struct color_float *val);
+
+void
+rgb_diff_stat_print(const struct rgb_diff_stat *stat,
+		    const char *title, unsigned scaling_bits);