Merge pull request #18 from tulir/ui-refactor

Refactor UI to use interfaces and add advanced message rendering

3 files changed, 672 insertions, 0 deletions

diff --git a/lib/ansimage/LICENSE b/lib/ansimage/LICENSE
new file mode 100644
index 0000000..14e2f77
--- /dev/null
+++ b/lib/ansimage/LICENSE
@@ -0,0 +1,373 @@
+Mozilla Public License Version 2.0
+==================================
+
+1. Definitions
+--------------
+
+1.1. "Contributor"
+    means each individual or legal entity that creates, contributes to
+    the creation of, or owns Covered Software.
+
+1.2. "Contributor Version"
+    means the combination of the Contributions of others (if any) used
+    by a Contributor and that particular Contributor's Contribution.
+
+1.3. "Contribution"
+    means Covered Software of a particular Contributor.
+
+1.4. "Covered Software"
+    means Source Code Form to which the initial Contributor has attached
+    the notice in Exhibit A, the Executable Form of such Source Code
+    Form, and Modifications of such Source Code Form, in each case
+    including portions thereof.
+
+1.5. "Incompatible With Secondary Licenses"
+    means
+
+    (a) that the initial Contributor has attached the notice described
+        in Exhibit B to the Covered Software; or
+
+    (b) that the Covered Software was made available under the terms of
+        version 1.1 or earlier of the License, but not also under the
+        terms of a Secondary License.
+
+1.6. "Executable Form"
+    means any form of the work other than Source Code Form.
+
+1.7. "Larger Work"
+    means a work that combines Covered Software with other material, in 
+    a separate file or files, that is not Covered Software.
+
+1.8. "License"
+    means this document.
+
+1.9. "Licensable"
+    means having the right to grant, to the maximum extent possible,
+    whether at the time of the initial grant or subsequently, any and
+    all of the rights conveyed by this License.
+
+1.10. "Modifications"
+    means any of the following:
+
+    (a) any file in Source Code Form that results from an addition to,
+        deletion from, or modification of the contents of Covered
+        Software; or
+
+    (b) any new file in Source Code Form that contains any Covered
+        Software.
+
+1.11. "Patent Claims" of a Contributor
+    means any patent claim(s), including without limitation, method,
+    process, and apparatus claims, in any patent Licensable by such
+    Contributor that would be infringed, but for the grant of the
+    License, by the making, using, selling, offering for sale, having
+    made, import, or transfer of either its Contributions or its
+    Contributor Version.
+
+1.12. "Secondary License"
+    means either the GNU General Public License, Version 2.0, the GNU
+    Lesser General Public License, Version 2.1, the GNU Affero General
+    Public License, Version 3.0, or any later versions of those
+    licenses.
+
+1.13. "Source Code Form"
+    means the form of the work preferred for making modifications.
+
+1.14. "You" (or "Your")
+    means an individual or a legal entity exercising rights under this
+    License. For legal entities, "You" includes any entity that
+    controls, is controlled by, or is under common control with You. For
+    purposes of this definition, "control" means (a) the power, direct
+    or indirect, to cause the direction or management of such entity,
+    whether by contract or otherwise, or (b) ownership of more than
+    fifty percent (50%) of the outstanding shares or beneficial
+    ownership of such entity.
+
+2. License Grants and Conditions
+--------------------------------
+
+2.1. Grants
+
+Each Contributor hereby grants You a world-wide, royalty-free,
+non-exclusive license:
+
+(a) under intellectual property rights (other than patent or trademark)
+    Licensable by such Contributor to use, reproduce, make available,
+    modify, display, perform, distribute, and otherwise exploit its
+    Contributions, either on an unmodified basis, with Modifications, or
+    as part of a Larger Work; and
+
+(b) under Patent Claims of such Contributor to make, use, sell, offer
+    for sale, have made, import, and otherwise transfer either its
+    Contributions or its Contributor Version.
+
+2.2. Effective Date
+
+The licenses granted in Section 2.1 with respect to any Contribution
+become effective for each Contribution on the date the Contributor first
+distributes such Contribution.
+
+2.3. Limitations on Grant Scope
+
+The licenses granted in this Section 2 are the only rights granted under
+this License. No additional rights or licenses will be implied from the
+distribution or licensing of Covered Software under this License.
+Notwithstanding Section 2.1(b) above, no patent license is granted by a
+Contributor:
+
+(a) for any code that a Contributor has removed from Covered Software;
+    or
+
+(b) for infringements caused by: (i) Your and any other third party's
+    modifications of Covered Software, or (ii) the combination of its
+    Contributions with other software (except as part of its Contributor
+    Version); or
+
+(c) under Patent Claims infringed by Covered Software in the absence of
+    its Contributions.
+
+This License does not grant any rights in the trademarks, service marks,
+or logos of any Contributor (except as may be necessary to comply with
+the notice requirements in Section 3.4).
+
+2.4. Subsequent Licenses
+
+No Contributor makes additional grants as a result of Your choice to
+distribute the Covered Software under a subsequent version of this
+License (see Section 10.2) or under the terms of a Secondary License (if
+permitted under the terms of Section 3.3).
+
+2.5. Representation
+
+Each Contributor represents that the Contributor believes its
+Contributions are its original creation(s) or it has sufficient rights
+to grant the rights to its Contributions conveyed by this License.
+
+2.6. Fair Use
+
+This License is not intended to limit any rights You have under
+applicable copyright doctrines of fair use, fair dealing, or other
+equivalents.
+
+2.7. Conditions
+
+Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted
+in Section 2.1.
+
+3. Responsibilities
+-------------------
+
+3.1. Distribution of Source Form
+
+All distribution of Covered Software in Source Code Form, including any
+Modifications that You create or to which You contribute, must be under
+the terms of this License. You must inform recipients that the Source
+Code Form of the Covered Software is governed by the terms of this
+License, and how they can obtain a copy of this License. You may not
+attempt to alter or restrict the recipients' rights in the Source Code
+Form.
+
+3.2. Distribution of Executable Form
+
+If You distribute Covered Software in Executable Form then:
+
+(a) such Covered Software must also be made available in Source Code
+    Form, as described in Section 3.1, and You must inform recipients of
+    the Executable Form how they can obtain a copy of such Source Code
+    Form by reasonable means in a timely manner, at a charge no more
+    than the cost of distribution to the recipient; and
+
+(b) You may distribute such Executable Form under the terms of this
+    License, or sublicense it under different terms, provided that the
+    license for the Executable Form does not attempt to limit or alter
+    the recipients' rights in the Source Code Form under this License.
+
+3.3. Distribution of a Larger Work
+
+You may create and distribute a Larger Work under terms of Your choice,
+provided that You also comply with the requirements of this License for
+the Covered Software. If the Larger Work is a combination of Covered
+Software with a work governed by one or more Secondary Licenses, and the
+Covered Software is not Incompatible With Secondary Licenses, this
+License permits You to additionally distribute such Covered Software
+under the terms of such Secondary License(s), so that the recipient of
+the Larger Work may, at their option, further distribute the Covered
+Software under the terms of either this License or such Secondary
+License(s).
+
+3.4. Notices
+
+You may not remove or alter the substance of any license notices
+(including copyright notices, patent notices, disclaimers of warranty,
+or limitations of liability) contained within the Source Code Form of
+the Covered Software, except that You may alter any license notices to
+the extent required to remedy known factual inaccuracies.
+
+3.5. Application of Additional Terms
+
+You may choose to offer, and to charge a fee for, warranty, support,
+indemnity or liability obligations to one or more recipients of Covered
+Software. However, You may do so only on Your own behalf, and not on
+behalf of any Contributor. You must make it absolutely clear that any
+such warranty, support, indemnity, or liability obligation is offered by
+You alone, and You hereby agree to indemnify every Contributor for any
+liability incurred by such Contributor as a result of warranty, support,
+indemnity or liability terms You offer. You may include additional
+disclaimers of warranty and limitations of liability specific to any
+jurisdiction.
+
+4. Inability to Comply Due to Statute or Regulation
+---------------------------------------------------
+
+If it is impossible for You to comply with any of the terms of this
+License with respect to some or all of the Covered Software due to
+statute, judicial order, or regulation then You must: (a) comply with
+the terms of this License to the maximum extent possible; and (b)
+describe the limitations and the code they affect. Such description must
+be placed in a text file included with all distributions of the Covered
+Software under this License. Except to the extent prohibited by statute
+or regulation, such description must be sufficiently detailed for a
+recipient of ordinary skill to be able to understand it.
+
+5. Termination
+--------------
+
+5.1. The rights granted under this License will terminate automatically
+if You fail to comply with any of its terms. However, if You become
+compliant, then the rights granted under this License from a particular
+Contributor are reinstated (a) provisionally, unless and until such
+Contributor explicitly and finally terminates Your grants, and (b) on an
+ongoing basis, if such Contributor fails to notify You of the
+non-compliance by some reasonable means prior to 60 days after You have
+come back into compliance. Moreover, Your grants from a particular
+Contributor are reinstated on an ongoing basis if such Contributor
+notifies You of the non-compliance by some reasonable means, this is the
+first time You have received notice of non-compliance with this License
+from such Contributor, and You become compliant prior to 30 days after
+Your receipt of the notice.
+
+5.2. If You initiate litigation against any entity by asserting a patent
+infringement claim (excluding declaratory judgment actions,
+counter-claims, and cross-claims) alleging that a Contributor Version
+directly or indirectly infringes any patent, then the rights granted to
+You by any and all Contributors for the Covered Software under Section
+2.1 of this License shall terminate.
+
+5.3. In the event of termination under Sections 5.1 or 5.2 above, all
+end user license agreements (excluding distributors and resellers) which
+have been validly granted by You or Your distributors under this License
+prior to termination shall survive termination.
+
+************************************************************************
+*                                                                      *
+*  6. Disclaimer of Warranty                                           *
+*  -------------------------                                           *
+*                                                                      *
+*  Covered Software is provided under this License on an "as is"       *
+*  basis, without warranty of any kind, either expressed, implied, or  *
+*  statutory, including, without limitation, warranties that the       *
+*  Covered Software is free of defects, merchantable, fit for a        *
+*  particular purpose or non-infringing. The entire risk as to the     *
+*  quality and performance of the Covered Software is with You.        *
+*  Should any Covered Software prove defective in any respect, You     *
+*  (not any Contributor) assume the cost of any necessary servicing,   *
+*  repair, or correction. This disclaimer of warranty constitutes an   *
+*  essential part of this License. No use of any Covered Software is   *
+*  authorized under this License except under this disclaimer.         *
+*                                                                      *
+************************************************************************
+
+************************************************************************
+*                                                                      *
+*  7. Limitation of Liability                                          *
+*  --------------------------                                          *
+*                                                                      *
+*  Under no circumstances and under no legal theory, whether tort      *
+*  (including negligence), contract, or otherwise, shall any           *
+*  Contributor, or anyone who distributes Covered Software as          *
+*  permitted above, be liable to You for any direct, indirect,         *
+*  special, incidental, or consequential damages of any character      *
+*  including, without limitation, damages for lost profits, loss of    *
+*  goodwill, work stoppage, computer failure or malfunction, or any    *
+*  and all other commercial damages or losses, even if such party      *
+*  shall have been informed of the possibility of such damages. This   *
+*  limitation of liability shall not apply to liability for death or   *
+*  personal injury resulting from such party's negligence to the       *
+*  extent applicable law prohibits such limitation. Some               *
+*  jurisdictions do not allow the exclusion or limitation of           *
+*  incidental or consequential damages, so this exclusion and          *
+*  limitation may not apply to You.                                    *
+*                                                                      *
+************************************************************************
+
+8. Litigation
+-------------
+
+Any litigation relating to this License may be brought only in the
+courts of a jurisdiction where the defendant maintains its principal
+place of business and such litigation shall be governed by laws of that
+jurisdiction, without reference to its conflict-of-law provisions.
+Nothing in this Section shall prevent a party's ability to bring
+cross-claims or counter-claims.
+
+9. Miscellaneous
+----------------
+
+This License represents the complete agreement concerning the subject
+matter hereof. If any provision of this License is held to be
+unenforceable, such provision shall be reformed only to the extent
+necessary to make it enforceable. Any law or regulation which provides
+that the language of a contract shall be construed against the drafter
+shall not be used to construe this License against a Contributor.
+
+10. Versions of the License
+---------------------------
+
+10.1. New Versions
+
+Mozilla Foundation is the license steward. Except as provided in Section
+10.3, no one other than the license steward has the right to modify or
+publish new versions of this License. Each version will be given a
+distinguishing version number.
+
+10.2. Effect of New Versions
+
+You may distribute the Covered Software under the terms of the version
+of the License under which You originally received the Covered Software,
+or under the terms of any subsequent version published by the license
+steward.
+
+10.3. Modified Versions
+
+If you create software not governed by this License, and you want to
+create a new license for such software, you may create and use a
+modified version of this License if you rename the license and remove
+any references to the name of the license steward (except to note that
+such modified license differs from this License).
+
+10.4. Distributing Source Code Form that is Incompatible With Secondary
+Licenses
+
+If You choose to distribute Source Code Form that is Incompatible With
+Secondary Licenses under the terms of this version of the License, the
+notice described in Exhibit B of this License must be attached.
+
+Exhibit A - Source Code Form License Notice
+-------------------------------------------
+
+  This Source Code Form is subject to the terms of the Mozilla Public
+  License, v. 2.0. If a copy of the MPL was not distributed with this
+  file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+If it is not possible or desirable to put the notice in a particular
+file, then You may include the notice in a location (such as a LICENSE
+file in a relevant directory) where a recipient would be likely to look
+for such a notice.
+
+You may add additional accurate notices of copyright ownership.
+
+Exhibit B - "Incompatible With Secondary Licenses" Notice
+---------------------------------------------------------
+
+  This Source Code Form is "Incompatible With Secondary Licenses", as
+  defined by the Mozilla Public License, v. 2.0.
diff --git a/lib/ansimage/ansimage.go b/lib/ansimage/ansimage.go
new file mode 100644
index 0000000..b117b3d
--- /dev/null
+++ b/lib/ansimage/ansimage.go
@@ -0,0 +1,287 @@
+//       ___  _____  ____
+//      / _ \/  _/ |/_/ /____ ______ _
+//     / ___// /_>  </ __/ -_) __/  ' \
+//    /_/  /___/_/|_|\__/\__/_/ /_/_/_/
+//
+//    Copyright 2017 Eliuk Blau
+//
+//    This Source Code Form is subject to the terms of the Mozilla Public
+//    License, v. 2.0. If a copy of the MPL was not distributed with this
+//    file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package ansimage
+
+import (
+	"errors"
+	"image"
+	"image/color"
+	"image/draw"
+	_ "image/gif"  // initialize decoder
+	_ "image/jpeg" // initialize decoder
+	_ "image/png"  // initialize decoder
+	"io"
+	"os"
+
+	"github.com/disintegration/imaging"
+	_ "golang.org/x/image/bmp"  // initialize decoder
+	_ "golang.org/x/image/tiff" // initialize decoder
+	_ "golang.org/x/image/webp" // initialize decoder
+	"maunium.net/go/gomuks/ui/messages/tstring"
+	"maunium.net/go/tcell"
+)
+
+var (
+	// ErrHeightNonMoT happens when ANSImage height is not a Multiple of Two value.
+	ErrHeightNonMoT = errors.New("ANSImage: height must be a Multiple of Two value")
+
+	// ErrInvalidBoundsMoT happens when ANSImage height or width are invalid values (Multiple of Two).
+	ErrInvalidBoundsMoT = errors.New("ANSImage: height or width must be >=2")
+
+	// ErrOutOfBounds happens when ANSI-pixel coordinates are out of ANSImage bounds.
+	ErrOutOfBounds = errors.New("ANSImage: out of bounds")
+)
+
+// ANSIpixel represents a pixel of an ANSImage.
+type ANSIpixel struct {
+	Brightness uint8
+	R, G, B    uint8
+	upper      bool
+	source     *ANSImage
+}
+
+// ANSImage represents an image encoded in ANSI escape codes.
+type ANSImage struct {
+	h, w     int
+	maxprocs int
+	bgR      uint8
+	bgG      uint8
+	bgB      uint8
+	pixmap   [][]*ANSIpixel
+}
+
+func (ai *ANSImage) Pixmap() [][]*ANSIpixel {
+	return ai.pixmap
+}
+
+// Height gets total rows of ANSImage.
+func (ai *ANSImage) Height() int {
+	return ai.h
+}
+
+// Width gets total columns of ANSImage.
+func (ai *ANSImage) Width() int {
+	return ai.w
+}
+
+// SetMaxProcs sets the maximum number of parallel goroutines to render the ANSImage
+// (user should manually sets `runtime.GOMAXPROCS(max)` before to this change takes effect).
+func (ai *ANSImage) SetMaxProcs(max int) {
+	ai.maxprocs = max
+}
+
+// GetMaxProcs gets the maximum number of parallels goroutines to render the ANSImage.
+func (ai *ANSImage) GetMaxProcs() int {
+	return ai.maxprocs
+}
+
+// SetAt sets ANSI-pixel color (RBG) and brightness in coordinates (y,x).
+func (ai *ANSImage) SetAt(y, x int, r, g, b, brightness uint8) error {
+	if y >= 0 && y < ai.h && x >= 0 && x < ai.w {
+		ai.pixmap[y][x].R = r
+		ai.pixmap[y][x].G = g
+		ai.pixmap[y][x].B = b
+		ai.pixmap[y][x].Brightness = brightness
+		ai.pixmap[y][x].upper = y%2 == 0
+		return nil
+	}
+	return ErrOutOfBounds
+}
+
+// GetAt gets ANSI-pixel in coordinates (y,x).
+func (ai *ANSImage) GetAt(y, x int) (*ANSIpixel, error) {
+	if y >= 0 && y < ai.h && x >= 0 && x < ai.w {
+		return &ANSIpixel{
+			R:          ai.pixmap[y][x].R,
+			G:          ai.pixmap[y][x].G,
+			B:          ai.pixmap[y][x].B,
+			Brightness: ai.pixmap[y][x].Brightness,
+			upper:      ai.pixmap[y][x].upper,
+			source:     ai.pixmap[y][x].source,
+		},
+			nil
+	}
+	return nil, ErrOutOfBounds
+}
+
+// Render returns the ANSI-compatible string form of ANSImage.
+// (Nice info for ANSI True Colour - https://gist.github.com/XVilka/8346728)
+func (ai *ANSImage) Render() []tstring.TString {
+	type renderData struct {
+		row    int
+		render tstring.TString
+	}
+
+	rows := make([]tstring.TString, ai.h/2)
+	for y := 0; y < ai.h; y += ai.maxprocs {
+		ch := make(chan renderData, ai.maxprocs)
+		for n, row := 0, y; (n <= ai.maxprocs) && (2*row+1 < ai.h); n, row = n+1, y+n {
+			go func(row, y int) {
+				str := make(tstring.TString, ai.w)
+				for x := 0; x < ai.w; x++ {
+					topPixel := ai.pixmap[y][x]
+					topColor := tcell.NewRGBColor(int32(topPixel.R), int32(topPixel.G), int32(topPixel.B))
+
+					bottomPixel := ai.pixmap[y+1][x]
+					bottomColor := tcell.NewRGBColor(int32(bottomPixel.R), int32(bottomPixel.G), int32(bottomPixel.B))
+
+					str[x] = tstring.Cell{
+						Char:  '▄',
+						Style: tcell.StyleDefault.Background(topColor).Foreground(bottomColor),
+					}
+				}
+				ch <- renderData{row: row, render: str}
+			}(row, 2*row)
+		}
+		for n, row := 0, y; (n <= ai.maxprocs) && (2*row+1 < ai.h); n, row = n+1, y+n {
+			data := <-ch
+			rows[data.row] = data.render
+		}
+	}
+	return rows
+}
+
+// New creates a new empty ANSImage ready to draw on it.
+func New(h, w int, bg color.Color) (*ANSImage, error) {
+	if h%2 != 0 {
+		return nil, ErrHeightNonMoT
+	}
+
+	if h < 2 || w < 2 {
+		return nil, ErrInvalidBoundsMoT
+	}
+
+	r, g, b, _ := bg.RGBA()
+	ansimage := &ANSImage{
+		h:        h, w: w,
+		maxprocs: 1,
+		bgR:      uint8(r),
+		bgG:      uint8(g),
+		bgB:      uint8(b),
+		pixmap:   nil,
+	}
+
+	ansimage.pixmap = func() [][]*ANSIpixel {
+		v := make([][]*ANSIpixel, h)
+		for y := 0; y < h; y++ {
+			v[y] = make([]*ANSIpixel, w)
+			for x := 0; x < w; x++ {
+				v[y][x] = &ANSIpixel{
+					R:          0,
+					G:          0,
+					B:          0,
+					Brightness: 0,
+					source:     ansimage,
+					upper:      y%2 == 0,
+				}
+			}
+		}
+		return v
+	}()
+
+	return ansimage, nil
+}
+
+// NewFromReader creates a new ANSImage from an io.Reader.
+// Background color is used to fill when image has transparency or dithering mode is enabled
+// Dithering mode is used to specify the way that ANSImage render ANSI-pixels (char/block elements).
+func NewFromReader(reader io.Reader, bg color.Color) (*ANSImage, error) {
+	img, _, err := image.Decode(reader)
+	if err != nil {
+		return nil, err
+	}
+
+	return createANSImage(img, bg)
+}
+
+// NewScaledFromReader creates a new scaled ANSImage from an io.Reader.
+// Background color is used to fill when image has transparency or dithering mode is enabled
+// Dithering mode is used to specify the way that ANSImage render ANSI-pixels (char/block elements).
+func NewScaledFromReader(reader io.Reader, y, x int, bg color.Color) (*ANSImage, error) {
+	img, _, err := image.Decode(reader)
+	if err != nil {
+		return nil, err
+	}
+
+	img = imaging.Resize(img, x, y, imaging.Lanczos)
+
+	return createANSImage(img, bg)
+}
+
+// NewFromFile creates a new ANSImage from a file.
+// Background color is used to fill when image has transparency or dithering mode is enabled
+// Dithering mode is used to specify the way that ANSImage render ANSI-pixels (char/block elements).
+func NewFromFile(name string, bg color.Color) (*ANSImage, error) {
+	reader, err := os.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	defer reader.Close()
+	return NewFromReader(reader, bg)
+}
+
+// NewScaledFromFile creates a new scaled ANSImage from a file.
+// Background color is used to fill when image has transparency or dithering mode is enabled
+// Dithering mode is used to specify the way that ANSImage render ANSI-pixels (char/block elements).
+func NewScaledFromFile(name string, y, x int, bg color.Color) (*ANSImage, error) {
+	reader, err := os.Open(name)
+	if err != nil {
+		return nil, err
+	}
+	defer reader.Close()
+	return NewScaledFromReader(reader, y, x, bg)
+}
+
+// createANSImage loads data from an image and returns an ANSImage.
+// Background color is used to fill when image has transparency or dithering mode is enabled
+// Dithering mode is used to specify the way that ANSImage render ANSI-pixels (char/block elements).
+func createANSImage(img image.Image, bg color.Color) (*ANSImage, error) {
+	var rgbaOut *image.RGBA
+	bounds := img.Bounds()
+
+	// do compositing only if background color has no transparency (thank you @disq for the idea!)
+	// (info - http://stackoverflow.com/questions/36595687/transparent-pixel-color-go-lang-image)
+	if _, _, _, a := bg.RGBA(); a >= 0xffff {
+		rgbaOut = image.NewRGBA(bounds)
+		draw.Draw(rgbaOut, bounds, image.NewUniform(bg), image.ZP, draw.Src)
+		draw.Draw(rgbaOut, bounds, img, image.ZP, draw.Over)
+	} else {
+		if v, ok := img.(*image.RGBA); ok {
+			rgbaOut = v
+		} else {
+			rgbaOut = image.NewRGBA(bounds)
+			draw.Draw(rgbaOut, bounds, img, image.ZP, draw.Src)
+		}
+	}
+
+	yMin, xMin := bounds.Min.Y, bounds.Min.X
+	yMax, xMax := bounds.Max.Y, bounds.Max.X
+
+	// always sets an even number of ANSIPixel rows...
+	yMax = yMax - yMax%2 // one for upper pixel and another for lower pixel --> without dithering
+
+	ansimage, err := New(yMax, xMax, bg)
+	if err != nil {
+		return nil, err
+	}
+
+	for y := yMin; y < yMax; y++ {
+		for x := xMin; x < xMax; x++ {
+			v := rgbaOut.RGBAAt(x, y)
+			if err := ansimage.SetAt(y, x, v.R, v.G, v.B, 0); err != nil {
+				return nil, err
+			}
+		}
+	}
+
+	return ansimage, nil
+}
diff --git a/lib/ansimage/doc.go b/lib/ansimage/doc.go
new file mode 100644
index 0000000..56bc0c5
--- /dev/null
+++ b/lib/ansimage/doc.go
@@ -0,0 +1,12 @@
+// Package ansimage is a simplified version of the ansimage package
+// in https://github.com/eliukblau/pixterm focused in rendering images
+// to a tcell-based TUI app.
+//
+//       ___  _____  ____
+//      / _ \/  _/ |/_/ /____ ______ _
+//     / ___// /_>  </ __/ -_) __/  ' \
+//    /_/  /___/_/|_|\__/\__/_/ /_/_/_/
+//
+// This package is licensed under the Mozilla Public License v2.0.
+package ansimage
+