tidy up docs and comments

README.md

@@ -8,7 +8,7 @@
 Package imaging provides basic image processing functions (resize, rotate, crop, brightness/contrast adjustments, etc.).
 
 All the image processing functions provided by the package accept any image type that implements `image.Image` interface
-as an input, and return a new image of `*image.NRGBA` type (32bit RGBA colors, not premultiplied by alpha).
+as an input, and return a new image of `*image.NRGBA` type (32bit RGBA colors, non-premultiplied alpha).
 
 ## Installation
 
@@ -39,13 +39,12 @@ dstImageFill := imaging.Fill(srcImage, 100, 100, imaging.Center, imaging.Lanczos
 ```
 
 Imaging supports image resizing using various resampling filters. The most notable ones:
-- `NearestNeighbor` - Fastest resampling filter, no antialiasing.
+- `Lanczos` - A high-quality resampling filter for photographic images yielding sharp results.
+- `CatmullRom` - A sharp cubic filter that is faster than Lanczos filter while providing similar results.
+- `MitchellNetravali` - A cubic filter that produces smoother results with less ringing artifacts than CatmullRom.
+- `Linear` - Bilinear resampling filter, produces smooth output. Faster than cubic filters.
 - `Box` - Simple and fast averaging filter appropriate for downscaling. When upscaling it's similar to NearestNeighbor.
-- `Linear` - Bilinear filter, smooth and reasonably fast.
-- `MitchellNetravali` - А smooth bicubic filter.
-- `CatmullRom` - A sharp bicubic filter.
-- `Gaussian` - Blurring filter that uses gaussian function, useful for noise removal.
-- `Lanczos` - High-quality resampling filter for photographic images yielding sharp results, slower than cubic filters.
+- `NearestNeighbor` - Fastest resampling filter, no antialiasing.
 
 The full list of supported filters:  NearestNeighbor, Box, Linear, Hermite, MitchellNetravali, CatmullRom, BSpline, Gaussian, Lanczos, Hann, Hamming, Blackman, Bartlett, Welch, Cosine. Custom filters can be created using ResampleFilter struct.
 

adjust.go

@@ -58,8 +58,8 @@ func Invert(img image.Image) *image.NRGBA {
 // The percentage = -100 gives the image with the saturation value zeroed for each pixel (grayscale).
 //
 // Examples:
-//  dstImage = imaging.AdjustSaturation(srcImage, 25) // increase image saturation by 25%
-//  dstImage = imaging.AdjustSaturation(srcImage, -10) // decrease image saturation by 10%
+//  dstImage = imaging.AdjustSaturation(srcImage, 25) // Increase image saturation by 25%.
+//  dstImage = imaging.AdjustSaturation(srcImage, -10) // Decrease image saturation by 10%.
 //
 func AdjustSaturation(img image.Image, percentage float64) *image.NRGBA {
 	percentage = math.Min(math.Max(percentage, -100), 100)
@@ -82,8 +82,8 @@ func AdjustSaturation(img image.Image, percentage float64) *image.NRGBA {
 //
 // Examples:
 //
-//	dstImage = imaging.AdjustContrast(srcImage, -10) // decrease image contrast by 10%
-//	dstImage = imaging.AdjustContrast(srcImage, 20) // increase image contrast by 20%
+//	dstImage = imaging.AdjustContrast(srcImage, -10) // Decrease image contrast by 10%.
+//	dstImage = imaging.AdjustContrast(srcImage, 20) // Increase image contrast by 20%.
 //
 func AdjustContrast(img image.Image, percentage float64) *image.NRGBA {
 	percentage = math.Min(math.Max(percentage, -100.0), 100.0)
@@ -109,8 +109,8 @@ func AdjustContrast(img image.Image, percentage float64) *image.NRGBA {
 //
 // Examples:
 //
-//	dstImage = imaging.AdjustBrightness(srcImage, -15) // decrease image brightness by 15%
-//	dstImage = imaging.AdjustBrightness(srcImage, 10) // increase image brightness by 10%
+//	dstImage = imaging.AdjustBrightness(srcImage, -15) // Decrease image brightness by 15%.
+//	dstImage = imaging.AdjustBrightness(srcImage, 10) // Increase image brightness by 10%.
 //
 func AdjustBrightness(img image.Image, percentage float64) *image.NRGBA {
 	percentage = math.Min(math.Max(percentage, -100.0), 100.0)
@@ -151,8 +151,8 @@ func AdjustGamma(img image.Image, gamma float64) *image.NRGBA {
 //
 // Examples:
 //
-//	dstImage = imaging.AdjustSigmoid(srcImage, 0.5, 3.0) // increase the contrast
-//	dstImage = imaging.AdjustSigmoid(srcImage, 0.5, -3.0) // decrease the contrast
+//	dstImage = imaging.AdjustSigmoid(srcImage, 0.5, 3.0) // Increase the contrast.
+//	dstImage = imaging.AdjustSigmoid(srcImage, 0.5, -3.0) // Decrease the contrast.
 //
 func AdjustSigmoid(img image.Image, midpoint, factor float64) *image.NRGBA {
 	if factor == 0 {
@@ -217,7 +217,7 @@ func adjustLUT(img image.Image, lut []uint8) *image.NRGBA {
 //	dstImage = imaging.AdjustFunc(
 //		srcImage,
 //		func(c color.NRGBA) color.NRGBA {
-//			// shift the red channel by 16
+//			// Shift the red channel by 16.
 //			r := int(c.R) + 16
 //			if r > 255 {
 //				r = 255

doc.go

@@ -2,6 +2,6 @@
 Package imaging provides basic image processing functions (resize, rotate, crop, brightness/contrast adjustments, etc.).
 
 All the image processing functions provided by the package accept any image type that implements image.Image interface
-as an input, and return a new image of *image.NRGBA type (32bit RGBA colors, not premultiplied by alpha).
+as an input, and return a new image of *image.NRGBA type (32bit RGBA colors, non-premultiplied alpha).
 */
 package imaging

effects.go

@@ -12,7 +12,7 @@ func gaussianBlurKernel(x, sigma float64) float64 {
 // Blur produces a blurred version of the image using a Gaussian function.
 // Sigma parameter must be positive and indicates how much the image will be blurred.
 //
-// Usage example:
+// Example:
 //
 //	dstImage := imaging.Blur(srcImage, 3.5)
 //
@@ -134,7 +134,7 @@ func blurVertical(img image.Image, kernel []float64) *image.NRGBA {
 // Sharpen produces a sharpened version of the image.
 // Sigma parameter must be positive and indicates how much the image will be sharpened.
 //
-// Usage example:
+// Example:
 //
 //	dstImage := imaging.Sharpen(srcImage, 3.5)
 //

resize.go

@@ -58,10 +58,7 @@ func precomputeWeights(dstSize, srcSize int, filter ResampleFilter) [][]indexWei
 // filter and returns the transformed image. If one of width or height is 0, the image aspect
 // ratio is preserved.
 //
-// Supported resample filters: NearestNeighbor, Box, Linear, Hermite, MitchellNetravali,
-// CatmullRom, BSpline, Gaussian, Lanczos, Hann, Hamming, Blackman, Bartlett, Welch, Cosine.
-//
-// Usage example:
+// Example:
 //
 //	dstImage := imaging.Resize(srcImage, 800, 600, imaging.Lanczos)
 //
@@ -218,10 +215,7 @@ func resizeNearest(img image.Image, width, height int) *image.NRGBA {
 // Fit scales down the image using the specified resample filter to fit the specified
 // maximum width and height and returns the transformed image.
 //
-// Supported resample filters: NearestNeighbor, Box, Linear, Hermite, MitchellNetravali,
-// CatmullRom, BSpline, Gaussian, Lanczos, Hann, Hamming, Blackman, Bartlett, Welch, Cosine.
-//
-// Usage example:
+// Example:
 //
 //	dstImage := imaging.Fit(srcImage, 800, 600, imaging.Lanczos)
 //
@@ -262,10 +256,7 @@ func Fit(img image.Image, width, height int, filter ResampleFilter) *image.NRGBA
 // Fill creates an image with the specified dimensions and fills it with the scaled source image.
 // To achieve the correct aspect ratio without stretching, the source image will be cropped.
 //
-// Supported resample filters: NearestNeighbor, Box, Linear, Hermite, MitchellNetravali,
-// CatmullRom, BSpline, Gaussian, Lanczos, Hann, Hamming, Blackman, Bartlett, Welch, Cosine.
-//
-// Usage example:
+// Example:
 //
 //	dstImage := imaging.Fill(srcImage, 800, 600, imaging.Center, imaging.Lanczos)
 //
@@ -344,10 +335,7 @@ func resizeAndCrop(img image.Image, width, height int, anchor Anchor, filter Res
 // Thumbnail scales the image up or down using the specified resample filter, crops it
 // to the specified width and hight and returns the transformed image.
 //
-// Supported resample filters: NearestNeighbor, Box, Linear, Hermite, MitchellNetravali,
-// CatmullRom, BSpline, Gaussian, Lanczos, Hann, Hamming, Blackman, Bartlett, Welch, Cosine.
-//
-// Usage example:
+// Example:
 //
 //	dstImage := imaging.Thumbnail(srcImage, 100, 100, imaging.Lanczos)
 //
@@ -355,29 +343,21 @@ func Thumbnail(img image.Image, width, height int, filter ResampleFilter) *image
 	return Fill(img, width, height, Center, filter)
 }
 
-// ResampleFilter is a resampling filter struct. It can be used to define custom filters.
-//
-// Supported resample filters: NearestNeighbor, Box, Linear, Hermite, MitchellNetravali,
-// CatmullRom, BSpline, Gaussian, Lanczos, Hann, Hamming, Blackman, Bartlett, Welch, Cosine.
+// ResampleFilter specifies a resampling filter to be used for image resizing.
 //
 //	General filter recommendations:
 //
 //	- Lanczos
-//		High-quality resampling filter for photographic images yielding sharp results.
-//		It's slower than cubic filters (see below).
+//		A high-quality resampling filter for photographic images yielding sharp results.
 //
 //	- CatmullRom
-//		A sharp cubic filter. It's a good filter for both upscaling and downscaling if sharp results are needed.
+//		A sharp cubic filter that is faster than Lanczos filter while providing similar results.
 //
 //	- MitchellNetravali
-//		A high quality cubic filter that produces smoother results with less ringing artifacts than CatmullRom.
-//
-//	- BSpline
-//		A good filter if a very smooth output is needed.
+//		A cubic filter that produces smoother results with less ringing artifacts than CatmullRom.
 //
 //	- Linear
-//		Bilinear interpolation filter, produces reasonably good, smooth output.
-//		It's faster than cubic filters.
+//		Bilinear resampling filter, produces a smooth output. Faster than cubic filters.
 //
 //	- Box
 //		Simple and fast averaging filter appropriate for downscaling.
@@ -412,7 +392,7 @@ var CatmullRom ResampleFilter
 // BSpline is a smooth cubic filter (BC-spline; B=1; C=0).
 var BSpline ResampleFilter
 
-// Gaussian is a Gaussian blurring Filter.
+// Gaussian is a Gaussian blurring filter.
 var Gaussian ResampleFilter
 
 // Bartlett is a Bartlett-windowed sinc filter (3 lobes).

tools.go

@@ -169,7 +169,7 @@ func PasteCenter(background, img image.Image) *image.NRGBA {
 // and returns the combined image. Opacity parameter is the opacity of the img
 // image layer, used to compose the images, it must be from 0.0 to 1.0.
 //
-// Usage examples:
+// Examples:
 //
 //	// Draw spriteImage over backgroundImage at the given position (x=50, y=50).
 //	dstImage := imaging.Overlay(backgroundImage, spriteImage, image.Pt(50, 50), 1.0)