[1.8] Two-way scroll bars

Earthcomputer · November 23, 2015

I'm making a client-side mod which requires a GUI which may be bigger that the physical screen size. I've looked at the vanilla code for scroll bars (in GuiSlot), but I don't understand it. How would I implement a two-way scroll bar such that:

Everything drawn on the screen is translated (shifted) in the opposite direction to the scroll bars
The mouse co-ordinates are translated in the same direction as the scroll bars, so it is easy to determine what was clicked

Are there examples of code that can already to this? If not, how would I go about implementing it?

Thanks in advance for help.

Edit: okay, I've made a start. It's just the commented parts of drawScreen I need help with now.


public class GuiTwoWayScroll extends GuiScreen {

private static final Method keyTypedMethod = ReflectionHelper.findMethod(GuiScreen.class, null,
		new String[] { "func_73869_a", "keyTyped" }, char.class, int.class);
private static final Method mouseClickedMethod = ReflectionHelper.findMethod(GuiScreen.class, null,
		new String[] { "func_73864_a", "mouseClicked" }, int.class, int.class, int.class);
private static final Method mouseReleasedMethod = ReflectionHelper.findMethod(GuiScreen.class, null,
		new String[] { "func_146286_b", "mouseReleased" }, int.class, int.class, int.class);
private static final Method mouseClickMoveMethod = ReflectionHelper.findMethod(GuiScreen.class, null,
		new String[] { "func_146273_a", "mouseClickMove" }, int.class, int.class, int.class, long.class);
private static final Method actionPerformedMethod = ReflectionHelper.findMethod(GuiScreen.class, null,
		new String[] { "func_146284_a", "actionPerformed" }, GuiButton.class);

protected float amtScrolledX;
protected float amtScrolledY;
protected GuiScreen child;

public GuiTwoWayScroll(GuiScreen child) {
	this.child = child;
}

@Override
public void drawScreen(int mouseX, int mouseY, float partialTicks) {
	// translate(amtScrolledX, amtScrolledY);
	child.drawScreen(mouseX + (int) amtScrolledX, mouseY + (int) amtScrolledY, partialTicks);
	// translate(-amtScrolledX, -amtScrolledY);
	// drawScrollBars();
}

@Override
protected void keyTyped(char typedChar, int keyCode) throws IOException {
	invokeSilently(keyTypedMethod, child, typedChar, keyCode);
}

@Override
protected void mouseClicked(int mouseX, int mouseY, int mouseButton) throws IOException {
	invokeSilently(mouseClickedMethod, child, mouseX + (int) amtScrolledX, mouseY + (int) amtScrolledY,
			mouseButton);
}

@Override
protected void mouseReleased(int mouseX, int mouseY, int state) {
	invokeSilently(mouseReleasedMethod, child, mouseX + (int) amtScrolledX, mouseY + (int) amtScrolledY, state);
}

@Override
protected void mouseClickMove(int mouseX, int mouseY, int clickedMouseButton, long timeSinceLastClick) {
	invokeSilently(mouseClickMoveMethod, child, mouseX + (int) amtScrolledX, mouseY + (int) amtScrolledY,
			clickedMouseButton, timeSinceLastClick);
}

@Override
protected void actionPerformed(GuiButton button) throws IOException {
	invokeSilently(actionPerformedMethod, child, button);
}

@Override
public void initGui() {
	child.initGui();
}

@Override
public void updateScreen() {
	child.updateScreen();
}

@Override
public void onGuiClosed() {
	child.onGuiClosed();
}

@Override
public void drawDefaultBackground() {
	child.drawDefaultBackground();
}

@Override
public void drawWorldBackground(int tint) {
	child.drawWorldBackground(tint);
}

@Override
public void drawBackground(int tint) {
	child.drawBackground(tint);
}

@Override
public boolean doesGuiPauseGame() {
	return child.doesGuiPauseGame();
}

@Override
public void confirmClicked(boolean result, int id) {
	child.confirmClicked(result, id);
}

private static Object invokeSilently(Method method, Object instance, Object... args) {
	Exception exception = null;
	try {
		return method.invoke(instance, args);
	} catch (IllegalAccessException e) {
		exception = e;
	} catch (IllegalArgumentException e) {
		exception = e;
	} catch (InvocationTargetException e) {
		exception = e;
	}
	throw new ReportedException(CrashReport.makeCrashReport(exception, "Doing reflection"));
}

}

Earthcomputer · November 30, 2015

Well, after a week of playing around with this, I think I've got a working solution which works for me (with just one small bug):

package net.earthcomputer.easyeditors.gui;

import java.io.IOException;

import org.lwjgl.input.Mouse;
import org.lwjgl.opengl.GL11;

import net.minecraft.client.gui.Gui;
import net.minecraft.client.gui.GuiScreen;
import net.minecraft.client.renderer.GlStateManager;
import net.minecraft.client.renderer.Tessellator;
import net.minecraft.client.renderer.WorldRenderer;
import net.minecraft.util.MathHelper;

public abstract class GuiTwoWayScroll extends GuiScreen {

private int headerHeight;
private int footerHeight;
private int virtualWidth;
private int virtualHeight;
private int scrollX;
private int scrollY;

private int shownWidth;
private int shownHeight;
private int maxScrollX;
private int maxScrollY;
private int xScrollBarWidth;
private int yScrollBarHeight;
private int xScrollBarLeft;
private int yScrollBarTop;
private int xScrollBarRight;
private int yScrollBarBottom;
private boolean xScrollBarVisible;
private boolean yScrollBarVisible;

private int firstXScrollBarPos = -1;
private int firstYScrollBarPos = -1;
private int firstMouseX = -1;
private int firstMouseY = -1;
private boolean leftButtonDown;

private int leftKey;
private int rightKey;
private int upKey;
private int downKey;
private boolean useMouseWheel = true;
private int xScrollBarPolicy;
private int yScrollBarPolicy;

public static final int SHOWN_NEVER = 0;
public static final int SHOWN_WHEN_NEEDED = 1;
public static final int SHOWN_ALWAYS = 2;

public GuiTwoWayScroll(int headerHeight, int footerHeight, int virtualWidth, int virtualHeight) {
	this.headerHeight = headerHeight;
	this.footerHeight = footerHeight;
	this.virtualWidth = virtualWidth;
	this.virtualHeight = virtualHeight;
	scrollX = scrollY = 0;
	xScrollBarPolicy = yScrollBarPolicy = SHOWN_WHEN_NEEDED;
}

private boolean hasInitialized = false;

@Override
public void initGui() {
	hasInitialized = true;
	refreshScrollBars();
}

private void refreshScrollBars() {
	if (!hasInitialized)
		return;
	switch (xScrollBarPolicy) {
	case SHOWN_NEVER:
		xScrollBarVisible = false;
		break;
	case SHOWN_WHEN_NEEDED:
		xScrollBarVisible = virtualWidth > width;
		break;
	case SHOWN_ALWAYS:
		xScrollBarVisible = true;
		break;
	default:
		throw new IllegalStateException("Illegal value for xScrollBarPolicy: " + xScrollBarPolicy);
	}
	shownHeight = height - headerHeight - footerHeight - (xScrollBarVisible ? 6 : 0);
	switch (yScrollBarPolicy) {
	case SHOWN_NEVER:
		yScrollBarVisible = false;
		break;
	case SHOWN_WHEN_NEEDED:
		yScrollBarVisible = virtualHeight > shownHeight;
		break;
	case SHOWN_ALWAYS:
		yScrollBarVisible = true;
		break;
	default:
		throw new IllegalStateException("Illegal value for yScrollBarPolicy: " + yScrollBarPolicy);
	}
	shownWidth = width - (yScrollBarVisible ? 6 : 0);
	if (yScrollBarVisible && !xScrollBarVisible && xScrollBarPolicy == SHOWN_WHEN_NEEDED
			&& virtualWidth > shownWidth) {
		xScrollBarVisible = true;
		shownHeight -= 6;
	}
	maxScrollX = virtualWidth - shownWidth;
	if (maxScrollX < 0)
		maxScrollX = 0;
	maxScrollY = virtualHeight - shownHeight;
	if (maxScrollY < 0)
		maxScrollY = 0;
	xScrollBarWidth = shownWidth * shownWidth / virtualWidth;
	if (xScrollBarWidth > shownWidth)
		xScrollBarWidth = shownWidth;
	yScrollBarHeight = shownHeight * shownHeight / virtualHeight;
	if (yScrollBarHeight > shownHeight)
		yScrollBarHeight = shownHeight;
	xScrollBarLeft = (maxScrollX == 0 ? 0 : (shownWidth - xScrollBarWidth) * scrollX / maxScrollX);
	yScrollBarTop = (maxScrollY == 0 ? 0 : (shownHeight - yScrollBarHeight) * scrollY / maxScrollY) + headerHeight;
	xScrollBarRight = xScrollBarLeft + xScrollBarWidth;
	yScrollBarBottom = yScrollBarTop + yScrollBarHeight;
	return;
}

public int getHeaderHeight() {
	return headerHeight;
}

public void setHeaderHeight(int headerHeight) {
	this.headerHeight = headerHeight;
	refreshScrollBars();
}

public int getFooterHeight() {
	return footerHeight;
}

public void setFooterHeight(int footerHeight) {
	this.footerHeight = footerHeight;
	refreshScrollBars();
}

public int getVirtualWidth() {
	return virtualWidth;
}

public void setVirtualWidth(int virtualWidth) {
	this.virtualWidth = virtualWidth;
	refreshScrollBars();
}

public int getVirtualHeight() {
	return virtualHeight;
}

public void setVirtualHeight(int virtualHeight) {
	this.virtualHeight = virtualHeight;
	refreshScrollBars();
}

public int getScrollX() {
	return scrollX;
}

public void setScrollX(int scrollX) {
	this.scrollX = MathHelper.clamp_int(scrollX, 0, maxScrollX);
	refreshScrollBars();
}

public void addScrollX(int scrollX) {
	setScrollX(this.scrollX + scrollX);
}

public int getScrollY() {
	return scrollY;
}

public void setScrollY(int scrollY) {
	this.scrollY = MathHelper.clamp_int(scrollY, 0, maxScrollY);
	refreshScrollBars();
}

public void addScrollY(int scrollY) {
	setScrollY(this.scrollY + scrollY);
}

public int getMaxScrollX() {
	return maxScrollX;
}

public int getMaxScrollY() {
	return maxScrollY;
}

public void scrollTo(int x, int y) {
	scrollX = MathHelper.clamp_int(x, 0, maxScrollX);
	scrollY = MathHelper.clamp_int(y, 0, maxScrollY);
	refreshScrollBars();
}

public int getShownWidth() {
	return shownWidth;
}

public int getShownHeight() {
	return shownHeight;
}

protected int getXScrollBarWidth() {
	return xScrollBarWidth;
}

protected int getYScrollBarHeight() {
	return yScrollBarHeight;
}

protected int getXScrollBarLeft() {
	return xScrollBarLeft;
}

protected int getYScrollBarTop() {
	return yScrollBarTop;
}

protected int getXScrollBarRight() {
	return xScrollBarRight;
}

protected int getYScrollBarBottom() {
	return yScrollBarBottom;
}

public int getXScrollBarPolicy() {
	return xScrollBarPolicy;
}

public void setXScrollBarPolicy(int xScrollBarPolicy) {
	this.xScrollBarPolicy = xScrollBarPolicy;
	refreshScrollBars();
}

public int getYScrollBarPolicy() {
	return yScrollBarPolicy;
}

public void setYScrollBarPolicy(int yScrollBarPolicy) {
	this.yScrollBarPolicy = yScrollBarPolicy;
	refreshScrollBars();
}

public int getLeftKey() {
	return leftKey;
}

public void setLeftKey(int leftKey) {
	this.leftKey = leftKey;
}

public int getRightKey() {
	return rightKey;
}

public void setRightKey(int rightKey) {
	this.rightKey = rightKey;
}

public int getUpKey() {
	return upKey;
}

public void setUpKey(int upKey) {
	this.upKey = upKey;
}

public int getDownKey() {
	return downKey;
}

public void setDownKey(int downKey) {
	this.downKey = downKey;
}

public boolean usesMouseWheel() {
	return useMouseWheel;
}

public void setUsesMouseWheel(boolean usesMouseWheel) {
	useMouseWheel = usesMouseWheel;
}

public void drawScreen(int mouseX, int mouseY, float partialTicks) {
	drawVirtualScreen(mouseX + scrollX, mouseY + scrollY - headerHeight, scrollX, scrollY, headerHeight);
	GlStateManager.disableLighting();
	GlStateManager.disableFog();
	Tessellator tessellator = Tessellator.getInstance();
	WorldRenderer worldRenderer = tessellator.getWorldRenderer();
	GlStateManager.disableDepth();

	overlayBackground(0, headerHeight);
	overlayBackground(height - footerHeight, footerHeight);
	drawForeground(mouseX, mouseY, partialTicks);

	GlStateManager.enableBlend();
	GlStateManager.tryBlendFuncSeparate(GL11.GL_SRC_ALPHA, GL11.GL_ONE_MINUS_SRC_ALPHA, 0, 1);
	GlStateManager.disableAlpha();
	GlStateManager.shadeModel(GL11.GL_SMOOTH);
	GlStateManager.disableTexture2D();

	if (yScrollBarVisible) {
		worldRenderer.startDrawingQuads();
		worldRenderer.setColorRGBA_I(0, 255);
		worldRenderer.addVertexWithUV(shownWidth, height - footerHeight, 0, 0, 1);
		worldRenderer.addVertexWithUV(width, height - footerHeight, 0, 1, 1);
		worldRenderer.addVertexWithUV(width, headerHeight, 0, 1, 0);
		worldRenderer.addVertexWithUV(shownWidth, headerHeight, 0, 0, 0);
		tessellator.draw();
	}
	if (xScrollBarVisible) {
		worldRenderer.startDrawingQuads();
		worldRenderer.setColorRGBA_I(0, 255);
		worldRenderer.addVertexWithUV(0, height - footerHeight, 0, 0, 1);
		worldRenderer.addVertexWithUV(width, height - footerHeight, 0, 1, 1);
		worldRenderer.addVertexWithUV(width, shownHeight + headerHeight, 0, 1, 0);
		worldRenderer.addVertexWithUV(0, shownHeight + headerHeight, 0, 0, 0);
		tessellator.draw();
	}
	if (xScrollBarVisible && yScrollBarVisible) {
		worldRenderer.startDrawingQuads();
		worldRenderer.setColorRGBA_I(0x808080, 255);
		worldRenderer.addVertexWithUV(shownWidth, height - footerHeight, 0, 0, 1);
		worldRenderer.addVertexWithUV(width, height - footerHeight, 0, 1, 1);
		worldRenderer.addVertexWithUV(width, shownHeight + headerHeight, 0, 1, 0);
		worldRenderer.addVertexWithUV(shownWidth, shownHeight + headerHeight, 0, 0, 0);
		tessellator.draw();
	}
	if (yScrollBarVisible) {
		worldRenderer.startDrawingQuads();
		worldRenderer.setColorRGBA_I(0x808080, 255);
		worldRenderer.addVertexWithUV(shownWidth, yScrollBarBottom, 0, 0, 1);
		worldRenderer.addVertexWithUV(width, yScrollBarBottom, 0, 1, 1);
		worldRenderer.addVertexWithUV(width, yScrollBarTop, 0, 1, 0);
		worldRenderer.addVertexWithUV(shownWidth, yScrollBarTop, 0, 0, 0);
		tessellator.draw();
	}
	if (xScrollBarVisible) {
		worldRenderer.startDrawingQuads();
		worldRenderer.setColorRGBA_I(0x808080, 255);
		worldRenderer.addVertexWithUV(xScrollBarLeft, height - footerHeight, 0, 0, 1);
		worldRenderer.addVertexWithUV(xScrollBarRight, height - footerHeight, 0, 1, 1);
		worldRenderer.addVertexWithUV(xScrollBarRight, shownHeight + headerHeight, 0, 1, 0);
		worldRenderer.addVertexWithUV(xScrollBarLeft, shownHeight + headerHeight, 0, 0, 0);
		tessellator.draw();
	}
	if (yScrollBarVisible) {
		worldRenderer.startDrawingQuads();
		worldRenderer.setColorRGBA_I(0xc0c0c0, 255);
		worldRenderer.addVertexWithUV(shownWidth, yScrollBarBottom - 1, 0, 0, 1);
		worldRenderer.addVertexWithUV(width - 1, yScrollBarBottom - 1, 0, 1, 1);
		worldRenderer.addVertexWithUV(width - 1, yScrollBarTop, 0, 1, 0);
		worldRenderer.addVertexWithUV(shownWidth, yScrollBarTop, 0, 0, 0);
		tessellator.draw();
	}
	if (xScrollBarVisible) {
		worldRenderer.startDrawingQuads();
		worldRenderer.setColorRGBA_I(0xc0c0c0, 255);
		worldRenderer.addVertexWithUV(xScrollBarLeft, height - footerHeight - 1, 0, 0, 1);
		worldRenderer.addVertexWithUV(xScrollBarRight - 1, height - footerHeight - 1, 0, 1, 1);
		worldRenderer.addVertexWithUV(xScrollBarRight - 1, shownHeight + headerHeight, 0, 1, 0);
		worldRenderer.addVertexWithUV(xScrollBarLeft, shownHeight + headerHeight, 0, 0, 0);
		tessellator.draw();
	}

	GlStateManager.enableTexture2D();
	GlStateManager.shadeModel(GL11.GL_FLAT);
	GlStateManager.enableAlpha();
	GlStateManager.disableBlend();

	super.drawScreen(mouseX, mouseY, partialTicks);
}

protected void overlayBackground(int top, int bottom) {
	Tessellator tessellator = Tessellator.getInstance();
	WorldRenderer worldRenderer = tessellator.getWorldRenderer();
	this.mc.getTextureManager().bindTexture(Gui.optionsBackground);
	GlStateManager.color(1, 1, 1, 1);
	worldRenderer.startDrawingQuads();
	worldRenderer.setColorRGBA_I(0x404040, 255);
	worldRenderer.addVertexWithUV(0, bottom, 0, 0, (float) bottom / 32);
	worldRenderer.addVertexWithUV(width, bottom, 0, (float) width / 32, (float) bottom / 32);
	worldRenderer.addVertexWithUV(width, top, 0, (float) this.width / 32, (float) top / 32);
	worldRenderer.addVertexWithUV(0, top, 0, 0, (float) top / 32);
	tessellator.draw();
}

protected abstract void drawVirtualScreen(int virtualMouseX, int virtualMouseY, int scrollX, int scrollY,
		int headerHeight);

protected abstract void drawForeground(int mouseX, int mouseY, float partialTicks);

@Override
public void keyTyped(char typedChar, int keyCode) throws IOException {
	if (keyCode == leftKey) {
		addScrollX(-20);
	} else if (keyCode == rightKey) {
		addScrollX(20);
	} else if (keyCode == upKey) {
		addScrollY(-20);
	} else if (keyCode == downKey) {
		addScrollY(20);
	} else {
		super.keyTyped(typedChar, keyCode);
	}
}

@Override
public void handleMouseInput() throws IOException {
	super.handleMouseInput();

	if (useMouseWheel) {
		int amtToScroll = Mouse.getEventDWheel();
		if (amtToScroll < 0)
			amtToScroll = 20;
		else if (amtToScroll > 0)
			amtToScroll = -20;
		addScrollY(amtToScroll);
	}
}

@Override
public void mouseClicked(int mouseX, int mouseY, int mouseButton) throws IOException {
	if (mouseButton == 0) {
		if (yScrollBarVisible && mouseX >= width - 6 && mouseY >= getYScrollBarTop() && mouseX < width
				&& mouseY < getYScrollBarBottom()) {
			firstYScrollBarPos = scrollY;
			firstMouseY = mouseY;
		} else if (xScrollBarVisible && mouseX >= getXScrollBarLeft() && mouseY >= headerHeight + shownHeight
				&& mouseX < getXScrollBarRight() && mouseY < height - footerHeight) {
			firstXScrollBarPos = scrollX;
			firstMouseX = mouseX;
		} else {
			mouseClickedVirtual(mouseX + scrollX, mouseY + scrollY - headerHeight, mouseButton);
		}
	} else if (mouseY > headerHeight && mouseY < height - footerHeight) {
		mouseClickedVirtual(mouseX + scrollX, mouseY + scrollY - headerHeight, mouseButton);
	}
	super.mouseClicked(mouseX, mouseY, mouseButton);
}

protected void mouseClickedVirtual(int virtualMouseX, int virtualMouseY, int mouseButton) {
}

@Override
public void mouseReleased(int mouseX, int mouseY, int state) {
	if (state == 0) { // This test does not work
		firstXScrollBarPos = firstYScrollBarPos = firstMouseX = firstMouseY = -1;
	}
	if (mouseY > headerHeight && mouseY < height - footerHeight)
		mouseReleasedVirtual(mouseX + scrollX, mouseY + scrollY - headerHeight, state);
	super.mouseReleased(mouseX, mouseY, state);
}

protected void mouseReleasedVirtual(int virtualMouseX, int virtualMouseY, int releasedButton) {
}

@Override
public void mouseClickMove(int mouseX, int mouseY, int clickedMouseButton, long timeSinceLastClick) {
	if (firstXScrollBarPos != -1) {
		int dx = mouseX - firstMouseX;
		float multiplier = (float) getShownWidth() / getXScrollBarWidth();
		setScrollX(firstXScrollBarPos + MathHelper.ceiling_float_int(dx * multiplier));
	} else if (firstYScrollBarPos != -1) {
		int dy = mouseY - firstMouseY;
		float multiplier = (float) getShownHeight() / getYScrollBarHeight();
		setScrollY(firstYScrollBarPos + MathHelper.ceiling_float_int(dy * multiplier));
	} else if (mouseY > headerHeight && mouseY < height - footerHeight) {
		mouseClickMoveVirtual(mouseX + scrollX, mouseY + scrollY - headerHeight, clickedMouseButton,
				timeSinceLastClick);
	}
}

protected void mouseClickMoveVirtual(int virtualMouseX, int virtualMouseY, int clickedMouseButton,
		long timeSinceLastClick) {
}

}

The small bug is in the method mouseReleased. Anyone know how to differentiate between different mouse buttons in that method?

coolAlias · November 30, 2015

#mouseReleased's 3rd parameter is the button that was released. To find out what the values are, put System.out.println("Released: " + state) in your method and play around in your GUI. 'Button' or 'released' would probably be better names than 'state' for that parameter.

Sign In

[1.8] Two-way scroll bars

Recommended Posts

Earthcomputer

Earthcomputer

coolAlias

Join the conversation

Announcements

Recently Browsing

Posts

Topics

Who's Online (See full list)

Browse

Activity

Important Information