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

// 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.

#include "TextBox.h"
#include <math.h>
#include <functional>

using namespace dsr;

PERSISTENT_DEFINITION(TextBox)

void TextBox::declareAttributes(StructureDefinition &target) const {
	VisualComponent::declareAttributes(target);
	target.declareAttribute(U"BackColor");
	target.declareAttribute(U"ForeColor");
	target.declareAttribute(U"Text");
}

Persistent* TextBox::findAttribute(const ReadableString &name) {
	if (string_caseInsensitiveMatch(name, U"BackColor")) {
		return &(this->backColor);
	} else if (string_caseInsensitiveMatch(name, U"ForeColor")) {
		return &(this->foreColor);
	} else if (string_caseInsensitiveMatch(name, U"Text")) {
		return &(this->text);
	} else if (string_caseInsensitiveMatch(name, U"MultiLine")) {
		return &(this->multiLine);
	} else {
		return VisualComponent::findAttribute(name);
	}
}

TextBox::TextBox() {}

bool TextBox::isContainer() const {
	return false;
}

// Limit exclusive indices to the text.
void TextBox::limitSelection() {
	int64_t textLength = string_length(this->text.value);
	if (this->selectionStart < 0) this->selectionStart = 0;
	if (this->beamLocation < 0) this->beamLocation = 0;
	if (this->selectionStart > textLength) this->selectionStart = textLength;
	if (this->beamLocation > textLength) this->beamLocation = textLength;
}

static void tabJump(int64_t &x, int64_t leftOrigin, int64_t tabWidth) {
	x += tabWidth - ((x - leftOrigin) % tabWidth);
}

// TODO: Make a separate version for multi-line textboxes.
// To have a stable tab alignment, the whole text must be given when iterating.
void iterateCharacters(const ReadableString& text, const RasterFont &font, int64_t originX, std::function<void(int64_t index, DsrChar code, int64_t left, int64_t right)> characterAction) {
	int64_t right = originX;
	int64_t tabWidth = font_getTabWidth(font);
	int64_t monospaceWidth = font_getMonospaceWidth(font);
	for (int64_t i = 0; i <= string_length(text); i++) {
		DsrChar code = text[i];
		int64_t left = right;
		if (code == U'\t') {
			tabJump(right, originX, tabWidth);
		} else {
			right += monospaceWidth;
		}
		characterAction(i, code, left, right);
	}
}

int64_t findBeamLocation(const ReadableString& text, const RasterFont &font, int64_t originX, int64_t findPixelX) {
	int64_t beamIndex = 0;
	int64_t closestDistance = 1000000000000;
	iterateCharacters(text, font, originX, [&beamIndex, &closestDistance, findPixelX](int64_t index, DsrChar code, int64_t left, int64_t right) {
		// TODO: Why is selection not centered? Is it the origin handled differently?
		int64_t center = (left + right) / 2;
		int64_t newDistance = std::abs(findPixelX - center);
		if (newDistance < closestDistance) {
			beamIndex = index;
			closestDistance = newDistance;
		}
	});
	return beamIndex;
}

// Iterate over the whole text once for both selection and characters.
// Returns the beam's X location in pixels relative to the parent of originX.
int64_t printMonospace(OrderedImageRgbaU8 &target, const ReadableString& text, const RasterFont &font, ColorRgbaI32 foreColor, bool focused, int64_t originX, int64_t selectionLeft, int64_t selectionRight, int64_t beamIndex, int64_t topY, int64_t bottomY) {
	int64_t characterHeight = bottomY - topY;
	int64_t beamPixelX = originX;
	iterateCharacters(text, font, originX, [&target, &font, &foreColor, &beamPixelX, selectionLeft, selectionRight, beamIndex, topY, characterHeight, focused](int64_t index, DsrChar code, int64_t left, int64_t right) {
		if (index == beamIndex) beamPixelX = left;
		if (focused && selectionLeft <= index && index < selectionRight) {
			draw_rectangle(target, IRect(left, topY, right - left, characterHeight), ColorRgbaI32(0, 0, 100, 255));
			font_printCharacter(target, font, code, IVector2D(left, topY), ColorRgbaI32(255, 255, 255, 255));
		} else {
			font_printCharacter(target, font, code, IVector2D(left, topY), foreColor);
		}
	});
	return beamPixelX;
}

// TODO: Reuse scaled background images as a separate layer.
// TODO: Allow using different colors for beam, selection, selected text, normal text...
//       Maybe ask a separate color palette for specific things using the specific class of textboxes.
//       Color palettes can be independent of the media machine, allowing them to be mixed freely with different themes.
//       Color palettes can be loaded together with the layout to instantly have the requested standard colors by name.
//       Color palettes can have a standard column order of input to easily pack multiple color themes into the same color palette image.
//         Just a long list of names for the different X coordinates and the user selects a Y coordinate as the color theme.
//         New components will have to use existing parts of the palette by keeping the names reusable.
//       Separate components should be able to override any color for programmability, but default values should refer to the current color palette.
//         If no color is assigned, the class will give it a standard color from the theme.
//         Should classes be separate for themes and palettes?
static OrderedImageRgbaU8 generateBoxImage(TextBox &textBox, MediaMethod imageGenerator, bool focused, int width, int height, ColorRgbaI32 backColor, ColorRgbaI32 foreColor, const ReadableString &text, const RasterFont &font) {
	// Create a scaled image
	OrderedImageRgbaU8 result;
 	textBox.generateImage(imageGenerator, width, height, backColor.red, backColor.green, backColor.blue, 0, focused ? 1 : 0)(result);
 	textBox.limitSelection();
 	// TODO: Allow moving the viewport to follow longer input.
 	// TODO: Allow multi-line textboxes with scrollbars.
 	//       The logic of scrollbars must be reused as value allocated objects across components, but with different settings.
	int64_t halfFontSize = font_getSize(font) / 2;
	int64_t originX = halfFontSize;
	int64_t center = image_getHeight(result) / 2;
	int64_t topY = center - halfFontSize;
	int64_t bottomY = center + halfFontSize;
	// Find character indices for left and right sides.
	int64_t selectionLeft = std::min(textBox.selectionStart, textBox.beamLocation);
	int64_t selectionRight = std::max(textBox.selectionStart, textBox.beamLocation);
	bool hasSelection = selectionLeft < selectionRight;
	// Draw the text with selection and get the beam's pixel location.
	int64_t beamPixelX = printMonospace(result, text, font, foreColor, focused, originX, selectionLeft, selectionRight, textBox.beamLocation, topY, bottomY);
	// Draw a beam if the textbox is focused.
	if (focused) {
		int64_t beamWidth = 2;
		draw_rectangle(result, IRect(beamPixelX - 1, topY - 1, beamWidth, bottomY - topY + 2), hasSelection ? ColorRgbaI32(255, 255, 255, 255) : foreColor);
	}
	return result;
}

void TextBox::generateGraphics() {
	int width = this->location.width();
	int height = this->location.height();
	if (width < 1) { width = 1; }
	if (height < 1) { height = 1; }
	bool currentlyFocused = this->isFocused();
	if (!this->hasImages || this->drawnAsFocused != currentlyFocused) {
		completeAssets();
		this->image = generateBoxImage(*this, this->textBox, currentlyFocused, width, height, ColorRgbaI32(this->backColor.value, 255), ColorRgbaI32(this->foreColor.value, 255), this->text.value, this->font);
		this->hasImages = true;
		this->drawnAsFocused = currentlyFocused;
	}
}

void TextBox::drawSelf(ImageRgbaU8& targetImage, const IRect &relativeLocation) {
	this->generateGraphics();
	draw_copy(targetImage, this->image, relativeLocation.left(), relativeLocation.top());
}

void TextBox::receiveMouseEvent(const MouseEvent& event) {
	int64_t originX = font_getSize(this->font) / 2;
	int32_t localMouseX = event.position.x - this->location.left();
	if (event.mouseEventType == MouseEventType::MouseDown) {
		this->mousePressed = true;
		int64_t newBeamIndex = findBeamLocation(this->text.value, this->font, originX, localMouseX);
		if (newBeamIndex != this->selectionStart || newBeamIndex != this->beamLocation) {
			this->selectionStart = newBeamIndex;
			this->beamLocation = newBeamIndex;
			this->hasImages = false;
		}
	} else if (this->mousePressed && event.mouseEventType == MouseEventType::MouseMove) {
		if (this->mousePressed) {
			int64_t newBeamIndex = findBeamLocation(this->text.value, this->font, originX, localMouseX);
			if (newBeamIndex != this->beamLocation) {
				this->beamLocation = newBeamIndex;
				this->hasImages = false;
			}
		}
	} else if (this->mousePressed && event.mouseEventType == MouseEventType::MouseUp) {
		this->mousePressed = false;
	}
	VisualComponent::receiveMouseEvent(event);
}

void TextBox::replaceSelection(const ReadableString replacingText) {
	int64_t selectionLeft = std::min(this->selectionStart, this->beamLocation);
	int64_t selectionRight = std::max(this->selectionStart, this->beamLocation);
	this->text.value = string_combine(string_before(this->text.value, selectionLeft), replacingText, string_from(this->text.value, selectionRight));
	// Place beam on the right side of the replacement without selecting anything
	this->selectionStart = selectionLeft + string_length(replacingText);
	this->beamLocation = selectionStart;
	this->hasImages = false;
}

void TextBox::replaceSelection(DsrChar replacingCharacter) {
	int64_t selectionLeft = std::min(this->selectionStart, this->beamLocation);
	int64_t selectionRight = std::max(this->selectionStart, this->beamLocation);
	String newText = string_before(this->text.value, selectionLeft);
	string_appendChar(newText, replacingCharacter);
	string_append(newText, string_from(this->text.value, selectionRight));
	this->text.value = newText;
	// Place beam on the right side of the replacement without selecting anything
	this->selectionStart = selectionLeft + 1;
	this->beamLocation = selectionStart;
	this->hasImages = false;
}

void TextBox::placeBeam(int64_t index, bool removeSelection) {
	this->beamLocation = index;
	if (removeSelection) {
		this->selectionStart = index;
	}
	this->hasImages = false;
}

static const uint32_t combinationKey_leftShift = 1 << 0;
static const uint32_t combinationKey_rightShift = 1 << 1;
static const uint32_t combinationKey_shift = combinationKey_leftShift | combinationKey_rightShift;
static const uint32_t combinationKey_leftControl = 1 << 2;
static const uint32_t combinationKey_rightControl = 1 << 3;
static const uint32_t combinationKey_control = combinationKey_leftControl | combinationKey_rightControl;

// TODO: Copy and paste using a clipboard.
void TextBox::receiveKeyboardEvent(const KeyboardEvent& event) {
	// Insert and scroll-lock is not supported.
	if (event.keyboardEventType == KeyboardEventType::KeyDown) {
		if (event.dsrKey == DsrKey_LeftShift) {
			this->combinationKeys |= combinationKey_leftShift;
		} else if (event.dsrKey == DsrKey_RightShift) {
			this->combinationKeys |= combinationKey_rightShift;
		} else if (event.dsrKey == DsrKey_LeftControl) {
			this->combinationKeys |= combinationKey_leftControl;
		} else if (event.dsrKey == DsrKey_RightControl) {
			this->combinationKeys |= combinationKey_rightControl;
		}
	} else if (event.keyboardEventType == KeyboardEventType::KeyUp) {
		if (event.dsrKey == DsrKey_LeftShift) {
			this->combinationKeys &= ~combinationKey_leftShift;
		} else if (event.dsrKey == DsrKey_RightShift) {
			this->combinationKeys &= ~combinationKey_rightShift;
		} else if (event.dsrKey == DsrKey_LeftControl) {
			this->combinationKeys &= ~combinationKey_leftControl;
		} else if (event.dsrKey == DsrKey_RightControl) {
			this->combinationKeys &= ~combinationKey_rightControl;
		}
	} else if (event.keyboardEventType == KeyboardEventType::KeyType) {
		int64_t textLength = string_length(this->text.value);
		bool selected = this->selectionStart != this->beamLocation;
		bool printable = event.character == U'\t' || (31 < event.character && event.character < 127) || 159 < event.character;
		bool canGoLeft = textLength > 0 && this->beamLocation > 0;
		bool canGoRight = textLength > 0 && this->beamLocation < textLength;
		bool holdShift = this->combinationKeys & combinationKey_shift;
		bool holdControl = this->combinationKeys & combinationKey_control;
		bool removeSelection = !holdShift;
		if (selected && (event.dsrKey == DsrKey_BackSpace || event.dsrKey == DsrKey_Delete)) {
			// Remove selection
			this->replaceSelection(U"");
		} else if (event.dsrKey == DsrKey_BackSpace && canGoLeft) {
			// Erase left of beam
			this->beamLocation--;
			this->replaceSelection(U"");
		} else if (event.dsrKey == DsrKey_Delete && canGoRight) {
			// Erase right of beam
			this->beamLocation++;
			this->replaceSelection(U"");
		} else if (event.dsrKey == DsrKey_Home || (event.dsrKey == DsrKey_LeftArrow && holdControl)) {
			// Move to the start using Home or Ctrl + LeftArrow
			this->placeBeam(0, removeSelection);
		} else if (event.dsrKey == DsrKey_End || (event.dsrKey == DsrKey_RightArrow && holdControl)) {
			// Move to the end using End or Ctrl + RightArrow
			this->placeBeam(textLength, removeSelection);
		} else if (event.dsrKey == DsrKey_LeftArrow && canGoLeft) {
			// Move left using LeftArrow
			this->placeBeam(this->beamLocation - 1, removeSelection);
		} else if (event.dsrKey == DsrKey_RightArrow && canGoRight) {
			// Move right using RightArrow
			this->placeBeam(this->beamLocation + 1, removeSelection);
		} else if (printable) {
			this->replaceSelection(event.character);
		}
		//printText(U"KeyType char=", event.character, " key=", event.dsrKey, U"\n");
	}
	VisualComponent::receiveKeyboardEvent(event);
}

bool TextBox::pointIsInside(const IVector2D& pixelPosition) {
	this->generateGraphics();
	// Get the point relative to the component instead of its direct container
	IVector2D localPoint = pixelPosition - this->location.upperLeft();
	// Sample opacity at the location
	return dsr::image_readPixel_border(this->image, localPoint.x, localPoint.y).alpha > 127;
}

void TextBox::changedTheme(VisualTheme newTheme) {
	this->textBox = theme_getScalableImage(newTheme, U"TextBox");
	this->hasImages = false;
}

void TextBox::completeAssets() {
	if (this->textBox.methodIndex == -1) {
		this->textBox = theme_getScalableImage(theme_getDefault(), U"TextBox");
	}
	if (this->font.get() == nullptr) {
		this->font = font_getDefault();
	}
}

void TextBox::changedLocation(const IRect &oldLocation, const IRect &newLocation) {
	// If the component has changed dimensions then redraw the image
	if (oldLocation.size() != newLocation.size()) {
		this->hasImages = false;
	}
}

void TextBox::changedAttribute(const ReadableString &name) {
	if (!string_caseInsensitiveMatch(name, U"Visible")) {
		this->hasImages = false;
		if (string_caseInsensitiveMatch(name, U"Text")) {
			this->limitSelection();
		}
	}
}