X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=vu_common.cpp;h=171f50d26a244059abcb1cab0cbd056565f6dbcc;hb=ffd68fbfb90242069af957f2a28908f0559f8348;hp=9fc3553eeb2fc907f21a1f7feea158b3c4236b20;hpb=fdd77c1f8a51f1e87151b876c2c5ab536a2fb02d;p=nageru

diff --git a/vu_common.cpp b/vu_common.cpp
index 9fc3553..171f50d 100644
--- a/vu_common.cpp
+++ b/vu_common.cpp
@@ -1,49 +1,73 @@
 #include "vu_common.h"
-#include <math.h>
+
+#include <QColor>
+#include <QPainter>
 #include <algorithm>
+#include <cmath>
 
 using namespace std;
 
-int lufs_to_pos(float level_lu, int height)
-{       
-	const float min_level = 9.0f;    // y=0 is top of screen, so “min” is the loudest level.
-	const float max_level = -18.0f;
+double lufs_to_pos(float level_lu, int height, float min_level, float max_level)
+{
+	// Note: “max” is the loudest level, but y=0 is top of screen.
 
 	// Handle -inf.
-	if (level_lu < max_level) {
+	if (level_lu < min_level) {
 		return height - 1;
 	}
 
-	int y = lrintf(height * (level_lu - min_level) / (max_level - min_level));
-	y = std::max(y, 0);
-	y = std::min(y, height - 1);
+	double y = height * (level_lu - max_level) / (min_level - max_level);
+	y = max<double>(y, 0);
+	y = min<double>(y, height - 1);
+
+	// If we are big enough, snap to pixel grid instead of antialiasing
+	// the edges; the unevenness will be less noticeable than the blurriness.
+	double height_per_level = height / (max_level - min_level) - 2.0;
+	if (height_per_level >= 10.0) {
+		y = round(y);
+	}
+
 	return y;
 }
 
-void draw_vu_meter(QPainter &painter, float range_low_lu, float range_high_lu, int width, int height, int margin)
+void draw_vu_meter(QPainter &painter, int width, int height, int horizontal_margin, double segment_margin, bool is_on, float min_level, float max_level, bool flip, int y_offset)
 {
-	painter.fillRect(margin, 0, width - 2 * margin, height, Qt::black);
-
-	// TODO: QLinearGradient is not gamma-correct; we might want to correct for that.
-	QLinearGradient on(0, 0, 0, height);
-	on.setColorAt(0.0f, QColor(255, 0, 0));
-	on.setColorAt(0.5f, QColor(255, 255, 0));
-	on.setColorAt(1.0f, QColor(0, 255, 0));
-	QColor off(80, 80, 80);
-
-	int min_on_y = lufs_to_pos(range_high_lu, height);
-	int max_on_y = lufs_to_pos(range_low_lu, height);
-
-	// Draw bars colored up until the level, then gray from there.
-	for (int level = -18; level < 9; ++level) {
-		int min_y = lufs_to_pos(level + 1.0f, height) + 1;
-		int max_y = lufs_to_pos(level, height) - 1;
-
-		painter.fillRect(margin, min_y, width - 2 * margin, max_y - min_y, off);
-		int min_draw_y = std::max(min_y, min_on_y);
-		int max_draw_y = std::min(max_y, max_on_y);
-		if (min_draw_y < max_draw_y) {
-			painter.fillRect(margin, min_draw_y, width - 2 * margin, max_draw_y - min_draw_y, on);
+	painter.fillRect(horizontal_margin, y_offset, width - 2 * horizontal_margin, height, Qt::black);
+
+	for (int y = 0; y < height; ++y) {
+		// Find coverage of “on” rectangles in this pixel row.
+		double coverage = 0.0;
+		for (int level = floor(min_level); level <= ceil(max_level); ++level) {
+			double min_y = lufs_to_pos(level + 1.0, height, min_level, max_level) + segment_margin * 0.5;
+			double max_y = lufs_to_pos(level, height, min_level, max_level) - segment_margin * 0.5;
+			min_y = std::max<double>(min_y, y);
+			min_y = std::min<double>(min_y, y + 1);
+			max_y = std::max<double>(max_y, y);
+			max_y = std::min<double>(max_y, y + 1);
+			coverage += max_y - min_y;
+		}
+
+		double on_r, on_g, on_b;
+		if (is_on) {
+			double t = double(y) / height;
+			if (t <= 0.5) {
+				on_r = 1.0;
+				on_g = 2.0 * t;
+				on_b = 0.0;
+			} else {
+				on_r = 1.0 - 2.0 * (t - 0.5);
+				on_g = 1.0;
+				on_b = 0.0;
+			}
+		} else {
+			on_r = on_g = on_b = 0.05;
 		}
+
+		// Correct for coverage and do a simple gamma correction.
+		int r = lrintf(255 * pow(on_r * coverage, 1.0 / 2.2));
+		int g = lrintf(255 * pow(on_g * coverage, 1.0 / 2.2));
+		int b = lrintf(255 * pow(on_b * coverage, 1.0 / 2.2));
+		int draw_y = flip ? (height - y - 1) : y;
+		painter.fillRect(horizontal_margin, draw_y + y_offset, width - 2 * horizontal_margin, 1, QColor(r, g, b));
 	}
 }