From ade6e6c060504002a4409fb0943432cf5c494872 Mon Sep 17 00:00:00 2001
From: Andrew Belt <andrewpbelt@gmail.com>
Date: Sun, 1 Aug 2021 17:47:40 -0400
Subject: [PATCH] Add nvgAlpha() and nvgTint() which multiply existing alpha
 and state instead of resetting it.

---
 src/nanovg.c | 14 ++++++++++++++
 src/nanovg.h |  2 ++
 2 files changed, 16 insertions(+)

diff --git a/src/nanovg.c b/src/nanovg.c
index 5fdbd66..0d00d48 100644
--- a/src/nanovg.c
+++ b/src/nanovg.c
@@ -716,6 +716,20 @@ NVGcolor nvgGetGlobalTint(NVGcontext* ctx)
 	return state->tint;
 }
 
+void nvgAlpha(NVGcontext* ctx, float alpha)
+{
+	NVGstate* state = nvg__getState(ctx);
+	state->tint.a *= alpha;
+}
+
+void nvgTint(NVGcontext* ctx, NVGcolor tint)
+{
+	NVGstate* state = nvg__getState(ctx);
+	int i;
+	for (i = 0; i < 4; i++)
+		state->tint.rgba[i] *= tint.rgba[i];
+}
+
 void nvgTransform(NVGcontext* ctx, float a, float b, float c, float d, float e, float f)
 {
 	NVGstate* state = nvg__getState(ctx);
diff --git a/src/nanovg.h b/src/nanovg.h
index b1c4e30..9210f5e 100644
--- a/src/nanovg.h
+++ b/src/nanovg.h
@@ -273,6 +273,8 @@ void nvgLineJoin(NVGcontext* ctx, int join);
 void nvgGlobalAlpha(NVGcontext* ctx, float alpha);
 void nvgGlobalTint(NVGcontext* ctx, NVGcolor tint);
 NVGcolor nvgGetGlobalTint(NVGcontext* ctx);
+void nvgAlpha(NVGcontext* ctx, float alpha);
+void nvgTint(NVGcontext* ctx, NVGcolor tint);
 
 //
 // Transforms