3DSoftwareRenderer-DFSPR/Source/DFPSR/gui/components/TextBox.h

// zlib open source license
//
// Copyright (c) 2022 David Forsgren Piuva
// 
// This software is provided 'as-is', without any express or implied
// warranty. In no event will the authors be held liable for any damages
// arising from the use of this software.
// 
// Permission is granted to anyone to use this software for any purpose,
// including commercial applications, and to alter it and redistribute it
// freely, subject to the following restrictions:
// 
//    1. The origin of this software must not be misrepresented; you must not
//    claim that you wrote the original software. If you use this software
//    in a product, an acknowledgment in the product documentation would be
//    appreciated but is not required.
// 
//    2. Altered source versions must be plainly marked as such, and must not be
//    misrepresented as being the original software.
// 
//    3. This notice may not be removed or altered from any source
//    distribution.

#ifndef DFPSR_GUI_COMPONENT_TEXTBOX
#define DFPSR_GUI_COMPONENT_TEXTBOX

#include "../VisualComponent.h"
#include "helpers/ScrollBarImpl.h"
#include "../../api/fontAPI.h"
#include "../../math/LVector.h"

// TODO: Make a theme for the horizontal scroll-bar and activate it.
// TODO: Prevent collisions between multiple scroll-bars in the corner by reserving a square in the corner when both are enabled.
// TODO: At least make a stub implementation for cutting, copying and pasting text within the same application.
//       Then make it optional to integrate the clipboard with the external operating system using a window handle from somewhere.
//       Copying within the same application is still useful if one has multiple files open at the same time or just need to move things around.

namespace dsr {

struct LineIndex {
	// Exclusive interval of characters in the line.
	int64_t lineStartIndex = 0;
	int64_t lineEndIndex = 0;
	LineIndex(int64_t lineStartIndex, int64_t lineEndIndex)
	: lineStartIndex(lineStartIndex), lineEndIndex(lineEndIndex) {}
};

struct BeamLocation {
	int64_t rowIndex; // Index of the current row.
	int64_t characterIndex; // Index of the character in the entire text.
	BeamLocation(int64_t rowIndex, int64_t characterIndex)
	: rowIndex(rowIndex), characterIndex(characterIndex) {}
};

class TextBox : public VisualComponent {
PERSISTENT_DECLARATION(TextBox)
public:
	// Value allocated sub-components
	// TODO: Let them know about each other to avoid overlap in the shared corner.
	ScrollBarImpl verticalScrollBar = ScrollBarImpl(true);
	ScrollBarImpl horizontalScrollBar = ScrollBarImpl(false);
	void updateScrollRange();
	void limitScrolling(bool keepBeamVisible);
	// Attributes
	PersistentColor foreColor;
	PersistentColor backColor;
	PersistentString text;
	PersistentBoolean multiLine;
	int64_t borderX = 6; // Empty pixels left and right of text.
	int64_t borderY = 4; // Empty pixels above and below text.
	// TODO: A setting for monospace?
	void declareAttributes(StructureDefinition &target) const override;
	Persistent* findAttribute(const ReadableString &name) override;
	// Temporary
	bool mousePressed = false;
	uint32_t combinationKeys = 0;
	// Selection goes from selectionStart to beamLocation using bi-directional exclusive character indices.
	//   Empty with selectionStart = beamLocation.
	//   From the left with selectionStart < beamLocation.
	//   From the right with beamLocation < selectionStart.
	int64_t selectionStart = 0;
	int64_t beamLocation = 0;
	// Pre-splitted version of text for fast rendering of large documents.
	List<LineIndex> lines;
	int64_t indexedAtLength = -1; // Length of the last indexed text to detect changes. Assign to -1 to force an update.
	int64_t worstCaseLineMonospaces = 0; // An approximation of the worst case line length in monospaces, counting tabs as full length to keep it simple.
	void indexLines();
	void limitSelection();
	LVector2D getTextOrigin(bool includeVerticalScroll);
	int64_t findBeamLocationInLine(int64_t rowIndex, int64_t pixelX);
	BeamLocation findBeamLocation(const LVector2D &pixelLocation);
	void replaceSelection(const ReadableString &replacingText);
	void replaceSelection(DsrChar replacingCharacter);
	void placeBeamAtCharacter(int64_t characterIndex, bool removeSelection);
	void moveBeamVertically(int64_t rowIndexOffset, bool removeSelection);
private:
	// Given from the style
	MediaMethod textBox;
	RasterFont font;
	void loadFont();
	void completeAssets();
	void generateGraphics();
	// Generated
	bool hasImages = false;
	bool drawnAsFocused = false;
	OrderedImageRgbaU8 image;
public:
	TextBox();
public:
	bool isContainer() const override;
	void drawSelf(ImageRgbaU8& targetImage, const IRect &relativeLocation) override;
	void receiveMouseEvent(const MouseEvent& event) override;
	void receiveKeyboardEvent(const KeyboardEvent& event) override;
	bool pointIsInside(const IVector2D& pixelPosition) override;
	void changedTheme(VisualTheme newTheme) override;
	void changedLocation(const IRect &oldLocation, const IRect &newLocation) override;
	void changedAttribute(const ReadableString &name) override;
};

}

#endif