From 5bd0ccce2e8edf7a3798b34ea1639649a70d7a75 Mon Sep 17 00:00:00 2001
From: Thomas Friedel <tomee6@gmail.com>
Date: Mon, 30 Apr 2018 16:30:19 +0200
Subject: [PATCH] updated docs

---
 canvas.go    |  2 ++
 gradients.go | 20 ++++++++++++++++++++
 images.go    |  2 +-
 text.go      |  9 +++++++++
 4 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/canvas.go b/canvas.go
index 6463f52..62b8fba 100644
--- a/canvas.go
+++ b/canvas.go
@@ -68,6 +68,7 @@ type scissor struct {
 type lineJoin uint8
 type lineEnd uint8
 
+// Line join and end constants for SetLineJoin and SetLineEnd
 const (
 	Miter = iota
 	Bevel
@@ -78,6 +79,7 @@ const (
 
 type textAlign uint8
 
+// Text alignment constants for SetTextAlign
 const (
 	Left = iota
 	Center
diff --git a/gradients.go b/gradients.go
index 641e00c..146a128 100644
--- a/gradients.go
+++ b/gradients.go
@@ -5,10 +5,18 @@ import (
 	"runtime"
 )
 
+// LinearGradient is a gradient with any number of
+// stops and any number of colors. The gradient will
+// be drawn such that each point on the gradient
+// will correspond to a straight line
 type LinearGradient struct {
 	gradient
 }
 
+// RadialGradient is a gradient with any number of
+// stops and any number of colors. The gradient will
+// be drawn such that each point on the gradient
+// will correspond to a circle
 type RadialGradient struct {
 	gradient
 	radFrom, radTo float64
@@ -27,6 +35,9 @@ type gradientStop struct {
 	color glColor
 }
 
+// NewLinearGradient creates a new linear gradient with
+// the coordinates from where to where the gradient
+// will apply on the canvas
 func NewLinearGradient(x0, y0, x1, y1 float64) *LinearGradient {
 	lg := &LinearGradient{gradient: gradient{from: vec{x0, y0}, to: vec{x1, y1}}}
 	gli.GenTextures(1, &lg.tex)
@@ -43,6 +54,10 @@ func NewLinearGradient(x0, y0, x1, y1 float64) *LinearGradient {
 	return lg
 }
 
+// NewRadialGradient creates a new linear gradient with
+// the coordinates and the radii for two circles. The
+// gradient will apply from the first to the second
+// circle
 func NewRadialGradient(x0, y0, r0, x1, y1, r1 float64) *RadialGradient {
 	rg := &RadialGradient{gradient: gradient{from: vec{x0, y0}, to: vec{x1, y1}}, radFrom: r0, radTo: r1}
 	gli.GenTextures(1, &rg.tex)
@@ -59,8 +74,10 @@ func NewRadialGradient(x0, y0, r0, x1, y1, r1 float64) *RadialGradient {
 	return rg
 }
 
+// Delete explicitly deletes the gradient
 func (g *gradient) Delete() {
 	gli.DeleteTextures(1, &g.tex)
+	g.deleted = true
 }
 
 func (g *gradient) load() {
@@ -113,6 +130,9 @@ func (g *gradient) colorAt(pos float64) glColor {
 	return c
 }
 
+// AddColorStop adds a color stop to the gradient. The stops
+// don't have to be added in order, they are sorted into the
+// right place
 func (g *gradient) AddColorStop(pos float64, color ...interface{}) {
 	c, _ := parseColor(color...)
 	insert := len(g.stops)
diff --git a/images.go b/images.go
index 620490e..be76c59 100644
--- a/images.go
+++ b/images.go
@@ -200,7 +200,7 @@ func (img *Image) Delete() {
 	img.deleted = true
 }
 
-// Draw image draws the given image to the given coordinates. The image
+// DrawImage draws the given image to the given coordinates. The image
 // parameter can be an Image loaded by LoadImage, a file name string that will
 // be loaded and cached, or a name string that corresponds to a previously
 // loaded image with the same name parameter.
diff --git a/text.go b/text.go
index d34dae1..41a1cf5 100644
--- a/text.go
+++ b/text.go
@@ -15,6 +15,8 @@ import (
 
 var fontRenderingContext = newFRContext()
 
+// Font is a loaded font that can be passed to the
+// SetFont method
 type Font struct {
 	font *truetype.Font
 }
@@ -25,6 +27,8 @@ var textImage *image.Alpha
 
 var defaultFont *Font
 
+// LoadFont loads a font and returns the result. The font
+// can be a file name or a byte slice in TTF format
 func LoadFont(src interface{}) (*Font, error) {
 	var f *Font
 	switch v := src.(type) {
@@ -55,6 +59,8 @@ func LoadFont(src interface{}) (*Font, error) {
 	return f, nil
 }
 
+// FillText draws the given string at the given coordinates
+// using the currently set font and font height
 func (cv *Canvas) FillText(str string, x, y float64) {
 	cv.activate()
 
@@ -225,10 +231,13 @@ func (cv *Canvas) FillText(str string, x, y float64) {
 	gli.StencilFunc(gl_ALWAYS, 0, 0xFF)
 }
 
+// TextMetrics is the result of a MeasureText call
 type TextMetrics struct {
 	Width float64
 }
 
+// MeasureText measures the given string using the
+// current font and font height
 func (cv *Canvas) MeasureText(str string) TextMetrics {
 	if cv.state.font == nil {
 		return TextMetrics{}