Unify scrollable list code
The goal of this patch set is to eliminate the code duplication
caused by copy/paste of the code in the file selector, listbox,
and partition list GUI elements. Those classes will now utilize a
single GUIScrollList class that will handle rendering and
scrolling.
Change-Id: I0cb98ab36cf47178296034293435225658c779cd
diff --git a/gui/scrolllist.cpp b/gui/scrolllist.cpp
new file mode 100644
index 0000000..9e8db4c
--- /dev/null
+++ b/gui/scrolllist.cpp
@@ -0,0 +1,709 @@
+/*
+ Copyright 2013 bigbiff/Dees_Troy TeamWin
+ This file is part of TWRP/TeamWin Recovery Project.
+
+ TWRP is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ TWRP is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with TWRP. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <string.h>
+
+extern "C" {
+#include "../twcommon.h"
+#include "../minuitwrp/minui.h"
+}
+
+#include "rapidxml.hpp"
+#include "objects.hpp"
+#include "../data.hpp"
+
+const int SCROLLING_SPEED_DECREMENT = 12; // friction
+const int SCROLLING_FLOOR = 10; // minimum pixels for scrolling to start or stop
+const int SCROLLING_MULTIPLIER = 2; // initial speed of kinetic scrolling
+const float SCROLLING_SPEED_LIMIT = 2.5; // maximum number of items to scroll per update
+
+GUIScrollList::GUIScrollList(xml_node<>* node) : GUIObject(node)
+{
+ xml_attribute<>* attr;
+ xml_node<>* child;
+ int header_separator_color_specified = 0, header_separator_height_specified = 0, header_text_color_specified = 0, header_background_color_specified = 0;
+
+ firstDisplayedItem = mItemSpacing = mFontHeight = mSeparatorH = y_offset = scrollingSpeed = 0;
+ maxIconWidth = maxIconHeight = mHeaderIconHeight = mHeaderIconWidth = 0;
+ mHeaderSeparatorH = mHeaderIsStatic = mHeaderH = actualItemHeight = 0;
+ mBackground = mFont = mHeaderIcon = NULL;
+ mBackgroundW = mBackgroundH = 0;
+ mFastScrollW = mFastScrollLineW = mFastScrollRectW = mFastScrollRectH = 0;
+ lastY = last2Y = fastScroll = 0;
+ mUpdate = 0;
+ touchDebounce = 6;
+ ConvertStrToColor("black", &mBackgroundColor);
+ ConvertStrToColor("black", &mHeaderBackgroundColor);
+ ConvertStrToColor("black", &mSeparatorColor);
+ ConvertStrToColor("black", &mHeaderSeparatorColor);
+ ConvertStrToColor("white", &mFontColor);
+ ConvertStrToColor("white", &mHeaderFontColor);
+ ConvertStrToColor("white", &mFastScrollLineColor);
+ ConvertStrToColor("white", &mFastScrollRectColor);
+ hasHighlightColor = false;
+ hasFontHighlightColor = false;
+ selectedItem = NO_ITEM;
+
+ // Load header text
+ child = node->first_node("header");
+ if (child)
+ {
+ attr = child->first_attribute("icon");
+ if (attr)
+ mHeaderIcon = PageManager::FindResource(attr->value());
+
+ attr = child->first_attribute("background");
+ if (attr)
+ {
+ std::string color = attr->value();
+ ConvertStrToColor(color, &mHeaderBackgroundColor);
+ header_background_color_specified = -1;
+ }
+ attr = child->first_attribute("textcolor");
+ if (attr)
+ {
+ std::string color = attr->value();
+ ConvertStrToColor(color, &mHeaderFontColor);
+ header_text_color_specified = -1;
+ }
+ attr = child->first_attribute("separatorcolor");
+ if (attr)
+ {
+ std::string color = attr->value();
+ ConvertStrToColor(color, &mHeaderSeparatorColor);
+ header_separator_color_specified = -1;
+ }
+ attr = child->first_attribute("separatorheight");
+ if (attr) {
+ string parsevalue = gui_parse_text(attr->value());
+ mHeaderSeparatorH = atoi(parsevalue.c_str());
+ header_separator_height_specified = -1;
+ }
+ }
+ child = node->first_node("text");
+ if (child) mHeaderText = child->value();
+
+ memset(&mHighlightColor, 0, sizeof(COLOR));
+ child = node->first_node("highlight");
+ if (child) {
+ attr = child->first_attribute("color");
+ if (attr) {
+ hasHighlightColor = true;
+ std::string color = attr->value();
+ ConvertStrToColor(color, &mHighlightColor);
+ }
+ }
+
+ // Simple way to check for static state
+ mLastHeaderValue = gui_parse_text(mHeaderText);
+ if (mLastHeaderValue != mHeaderText)
+ mHeaderIsStatic = 0;
+ else
+ mHeaderIsStatic = -1;
+
+ child = node->first_node("background");
+ if (child)
+ {
+ attr = child->first_attribute("resource");
+ if (attr)
+ mBackground = PageManager::FindResource(attr->value());
+ attr = child->first_attribute("color");
+ if (attr)
+ {
+ std::string color = attr->value();
+ ConvertStrToColor(color, &mBackgroundColor);
+ if (!header_background_color_specified)
+ ConvertStrToColor(color, &mHeaderBackgroundColor);
+ }
+ }
+
+ // Load the placement
+ LoadPlacement(node->first_node("placement"), &mRenderX, &mRenderY, &mRenderW, &mRenderH);
+ SetActionPos(mRenderX, mRenderY, mRenderW, mRenderH);
+
+ // Load the font, and possibly override the color
+ child = node->first_node("font");
+ if (child)
+ {
+ attr = child->first_attribute("resource");
+ if (attr)
+ mFont = PageManager::FindResource(attr->value());
+
+ attr = child->first_attribute("color");
+ if (attr)
+ {
+ std::string color = attr->value();
+ ConvertStrToColor(color, &mFontColor);
+ if (!header_text_color_specified)
+ ConvertStrToColor(color, &mHeaderFontColor);
+ }
+
+ attr = child->first_attribute("spacing");
+ if (attr) {
+ string parsevalue = gui_parse_text(attr->value());
+ mItemSpacing = atoi(parsevalue.c_str());
+ }
+
+ attr = child->first_attribute("highlightcolor");
+ memset(&mFontHighlightColor, 0, sizeof(COLOR));
+ if (attr)
+ {
+ std::string color = attr->value();
+ ConvertStrToColor(color, &mFontHighlightColor);
+ hasFontHighlightColor = true;
+ }
+ }
+
+ // Load the separator if it exists
+ child = node->first_node("separator");
+ if (child)
+ {
+ attr = child->first_attribute("color");
+ if (attr)
+ {
+ std::string color = attr->value();
+ ConvertStrToColor(color, &mSeparatorColor);
+ if (!header_separator_color_specified)
+ ConvertStrToColor(color, &mHeaderSeparatorColor);
+ }
+
+ attr = child->first_attribute("height");
+ if (attr) {
+ string parsevalue = gui_parse_text(attr->value());
+ mSeparatorH = atoi(parsevalue.c_str());
+ if (!header_separator_height_specified)
+ mHeaderSeparatorH = mSeparatorH;
+ }
+ }
+
+ // Fast scroll colors
+ child = node->first_node("fastscroll");
+ if (child)
+ {
+ attr = child->first_attribute("linecolor");
+ if(attr)
+ ConvertStrToColor(attr->value(), &mFastScrollLineColor);
+
+ attr = child->first_attribute("rectcolor");
+ if(attr)
+ ConvertStrToColor(attr->value(), &mFastScrollRectColor);
+
+ attr = child->first_attribute("w");
+ if (attr) {
+ string parsevalue = gui_parse_text(attr->value());
+ mFastScrollW = atoi(parsevalue.c_str());
+ }
+
+ attr = child->first_attribute("linew");
+ if (attr) {
+ string parsevalue = gui_parse_text(attr->value());
+ mFastScrollLineW = atoi(parsevalue.c_str());
+ }
+
+ attr = child->first_attribute("rectw");
+ if (attr) {
+ string parsevalue = gui_parse_text(attr->value());
+ mFastScrollRectW = atoi(parsevalue.c_str());
+ }
+
+ attr = child->first_attribute("recth");
+ if (attr) {
+ string parsevalue = gui_parse_text(attr->value());
+ mFastScrollRectH = atoi(parsevalue.c_str());
+ }
+ }
+
+ // Retrieve the line height
+ mFontHeight = gr_getMaxFontHeight(mFont ? mFont->GetResource() : NULL);
+ mHeaderH = mFontHeight;
+
+ if (mHeaderIcon && mHeaderIcon->GetResource())
+ {
+ mHeaderIconWidth = gr_get_width(mHeaderIcon->GetResource());
+ mHeaderIconHeight = gr_get_height(mHeaderIcon->GetResource());
+ if (mHeaderIconHeight > mHeaderH)
+ mHeaderH = mHeaderIconHeight;
+ if (mHeaderIconWidth > maxIconWidth)
+ maxIconWidth = mHeaderIconWidth;
+ }
+
+ mHeaderH += mItemSpacing + mHeaderSeparatorH;
+ actualItemHeight = mFontHeight + mItemSpacing + mSeparatorH;
+ if (mHeaderH < actualItemHeight)
+ mHeaderH = actualItemHeight;
+
+ if (actualItemHeight / 3 > 6)
+ touchDebounce = actualItemHeight / 3;
+
+ if (mBackground && mBackground->GetResource())
+ {
+ mBackgroundW = gr_get_width(mBackground->GetResource());
+ mBackgroundH = gr_get_height(mBackground->GetResource());
+ }
+}
+
+GUIScrollList::~GUIScrollList()
+{
+ delete mHeaderIcon;
+ delete mBackground;
+ delete mFont;
+}
+
+void GUIScrollList::SetMaxIconSize(int w, int h)
+{
+ if (w > maxIconWidth)
+ maxIconWidth = w;
+ if (h > maxIconHeight)
+ maxIconHeight = h;
+ if (maxIconHeight > mFontHeight) {
+ actualItemHeight = maxIconHeight + mItemSpacing + mSeparatorH;
+ if (actualItemHeight > mHeaderH)
+ mHeaderH = actualItemHeight;
+ }
+}
+
+void GUIScrollList::SetVisibleListLocation(size_t list_index)
+{
+ // This will make sure that the item indicated by list_index is visible on the screen
+ size_t lines = GetDisplayItemCount(), listSize = GetItemCount();
+
+ if (list_index <= (unsigned)firstDisplayedItem) {
+ // list_index is above the currently displayed items, put the selected item at the very top
+ firstDisplayedItem = list_index;
+ y_offset = 0;
+ } else if (list_index >= firstDisplayedItem + lines) {
+ // list_index is below the currently displayed items, put the selected item at the very bottom
+ firstDisplayedItem = list_index - lines + 1;
+ if (GetDisplayRemainder() != 0) {
+ // There's a partial row displayed, set the scrolling offset so that the selected item really is at the very bottom
+ firstDisplayedItem--;
+ y_offset = GetDisplayRemainder() - actualItemHeight;
+ } else {
+ // There's no partial row so zero out the offset
+ y_offset = 0;
+ }
+ }
+ scrollingSpeed = 0; // stop kinetic scrolling on setting visible location
+ mUpdate = 1;
+}
+
+int GUIScrollList::Render(void)
+{
+ if(!isConditionTrue())
+ return 0;
+
+ // First step, fill background
+ gr_color(mBackgroundColor.red, mBackgroundColor.green, mBackgroundColor.blue, 255);
+ gr_fill(mRenderX, mRenderY + mHeaderH, mRenderW, mRenderH - mHeaderH);
+
+ // Next, render the background resource (if it exists)
+ if (mBackground && mBackground->GetResource())
+ {
+ int mBackgroundX = mRenderX + ((mRenderW - mBackgroundW) / 2);
+ int mBackgroundY = mRenderY + ((mRenderH - mBackgroundH) / 2);
+ gr_blit(mBackground->GetResource(), 0, 0, mBackgroundW, mBackgroundH, mBackgroundX, mBackgroundY);
+ }
+
+ // This tells us how many lines we can actually render
+ size_t lines = GetDisplayItemCount();
+
+ size_t listSize = GetItemCount();
+ int listW = mRenderW;
+
+ if (listSize <= lines) {
+ hasScroll = false;
+ scrollingSpeed = 0;
+ lines = listSize;
+ y_offset = 0;
+ } else {
+ hasScroll = true;
+ listW -= mFastScrollW; // space for fast scroll
+ lines++;
+ if (lines < listSize)
+ lines++;
+ }
+
+ void* fontResource = NULL;
+ if (mFont) fontResource = mFont->GetResource();
+
+ int yPos = mRenderY + mHeaderH + y_offset;
+ int fontOffsetY = (int)((actualItemHeight - mFontHeight) / 2);
+
+ // render all visible items
+ for (size_t line = 0; line < lines; line++)
+ {
+ size_t itemindex = line + firstDisplayedItem;
+ if (itemindex >= listSize)
+ break;
+
+ // get item data
+ Resource* icon;
+ std::string label;
+ if (GetListItem(itemindex, icon, label))
+ break;
+
+ if (hasHighlightColor && itemindex == selectedItem) {
+ // Highlight the item background of the selected item
+ gr_color(mHighlightColor.red, mHighlightColor.green, mHighlightColor.blue, 255);
+ int HighlightHeight = actualItemHeight;
+ if (yPos + HighlightHeight > mRenderY + mRenderH) {
+ HighlightHeight = mRenderY + mRenderH - yPos;
+ }
+ gr_fill(mRenderX, yPos, mRenderW, HighlightHeight);
+ }
+
+ if (hasFontHighlightColor && itemindex == selectedItem) {
+ // Use the highlight color for the font
+ gr_color(mFontHighlightColor.red, mFontHighlightColor.green, mFontHighlightColor.blue, 255);
+ } else {
+ // Set the color for the font
+ gr_color(mFontColor.red, mFontColor.green, mFontColor.blue, 255);
+ }
+
+ if (icon && icon->GetResource()) {
+ int currentIconHeight = gr_get_height(icon->GetResource());
+ int currentIconWidth = gr_get_width(icon->GetResource());
+ int currentIconOffsetY = (int)((actualItemHeight - currentIconHeight) / 2);
+ int currentIconOffsetX = (maxIconWidth - currentIconWidth) / 2;
+ int rect_y = 0, image_y = (yPos + currentIconOffsetY);
+ if (image_y + currentIconHeight > mRenderY + mRenderH)
+ rect_y = mRenderY + mRenderH - image_y;
+ else
+ rect_y = currentIconHeight;
+ gr_blit(icon->GetResource(), 0, 0, currentIconWidth, rect_y, mRenderX + currentIconOffsetX, image_y);
+ }
+
+ gr_textExWH(mRenderX + maxIconWidth + 5, yPos + fontOffsetY, label.c_str(), fontResource, mRenderX + listW, mRenderY + mRenderH);
+
+ // Add the separator
+ if (yPos + actualItemHeight < mRenderH + mRenderY) {
+ gr_color(mSeparatorColor.red, mSeparatorColor.green, mSeparatorColor.blue, 255);
+ gr_fill(mRenderX, yPos + actualItemHeight - mSeparatorH, listW, mSeparatorH);
+ }
+
+ // Move the yPos
+ yPos += actualItemHeight;
+ }
+
+ // Render the Header (last so that it overwrites the top most row for per pixel scrolling)
+ // First step, fill background
+ gr_color(mHeaderBackgroundColor.red, mHeaderBackgroundColor.green, mHeaderBackgroundColor.blue, 255);
+ gr_fill(mRenderX, mRenderY, mRenderW, mHeaderH);
+
+ // Now, we need the header (icon + text)
+ yPos = mRenderY;
+ {
+ Resource* headerIcon;
+ int mIconOffsetX = 0;
+
+ // render the icon if it exists
+ headerIcon = mHeaderIcon;
+ if (headerIcon && headerIcon->GetResource())
+ {
+ gr_blit(headerIcon->GetResource(), 0, 0, mHeaderIconWidth, mHeaderIconHeight, mRenderX + ((mHeaderIconWidth - maxIconWidth) / 2), (yPos + (int)((mHeaderH - mHeaderIconHeight) / 2)));
+ mIconOffsetX = maxIconWidth;
+ }
+
+ // render the text
+ gr_color(mHeaderFontColor.red, mHeaderFontColor.green, mHeaderFontColor.blue, 255);
+ gr_textExWH(mRenderX + mIconOffsetX + 5, yPos + (int)((mHeaderH - mFontHeight) / 2), mLastHeaderValue.c_str(), fontResource, mRenderX + mRenderW, mRenderY + mRenderH);
+
+ // Add the separator
+ gr_color(mHeaderSeparatorColor.red, mHeaderSeparatorColor.green, mHeaderSeparatorColor.blue, 255);
+ gr_fill(mRenderX, yPos + mHeaderH - mHeaderSeparatorH, mRenderW, mHeaderSeparatorH);
+ }
+
+ // render fast scroll
+ lines = GetDisplayItemCount();
+ if (hasScroll) {
+ int startX = listW + mRenderX;
+ int fWidth = mRenderW - listW;
+ int fHeight = mRenderH - mHeaderH;
+
+ // line
+ gr_color(mFastScrollLineColor.red, mFastScrollLineColor.green, mFastScrollLineColor.blue, 255);
+ gr_fill(startX + fWidth/2, mRenderY + mHeaderH, mFastScrollLineW, mRenderH - mHeaderH);
+
+ // rect
+ int pct = 0;
+ if (GetDisplayRemainder() != 0) {
+ // Properly handle the percentage if a partial line is present
+ int partial_line_size = actualItemHeight - GetDisplayRemainder();
+ pct = ((firstDisplayedItem*actualItemHeight - y_offset)*100)/(listSize*actualItemHeight-((lines + 1)*actualItemHeight) + partial_line_size);
+ } else {
+ pct = ((firstDisplayedItem*actualItemHeight - y_offset)*100)/(listSize*actualItemHeight-lines*actualItemHeight);
+ }
+ int mFastScrollRectX = startX + (fWidth - mFastScrollRectW)/2;
+ int mFastScrollRectY = mRenderY+mHeaderH + ((fHeight - mFastScrollRectH)*pct)/100;
+
+ gr_color(mFastScrollRectColor.red, mFastScrollRectColor.green, mFastScrollRectColor.blue, 255);
+ gr_fill(mFastScrollRectX, mFastScrollRectY, mFastScrollRectW, mFastScrollRectH);
+ }
+ mUpdate = 0;
+ return 0;
+}
+
+int GUIScrollList::Update(void)
+{
+ if(!isConditionTrue())
+ return 0;
+
+ if (!mHeaderIsStatic) {
+ std::string newValue = gui_parse_text(mHeaderText);
+ if (mLastHeaderValue != newValue) {
+ mLastHeaderValue = newValue;
+ mUpdate = 1;
+ }
+ }
+
+ // Handle kinetic scrolling
+ int maxScrollDistance = actualItemHeight * SCROLLING_SPEED_LIMIT;
+ if (scrollingSpeed == 0) {
+ // Do nothing
+ return 0;
+ } else if (scrollingSpeed > 0) {
+ if (scrollingSpeed < maxScrollDistance)
+ y_offset += scrollingSpeed;
+ else
+ y_offset += maxScrollDistance;
+ scrollingSpeed -= SCROLLING_SPEED_DECREMENT;
+ } else if (scrollingSpeed < 0) {
+ if (abs(scrollingSpeed) < maxScrollDistance)
+ y_offset += scrollingSpeed;
+ else
+ y_offset -= maxScrollDistance;
+ scrollingSpeed += SCROLLING_SPEED_DECREMENT;
+ }
+ if (abs(scrollingSpeed) < SCROLLING_FLOOR)
+ scrollingSpeed = 0;
+ HandleScrolling();
+ mUpdate = 1;
+
+ return 0;
+}
+
+size_t GUIScrollList::HitTestItem(int x, int y)
+{
+ // We only care about y position
+ if (y < mRenderY || y - mRenderY <= mHeaderH || y - mRenderY > mRenderH)
+ return NO_ITEM;
+
+ int startSelection = (y - mRenderY - mHeaderH);
+
+ // Locate the correct item
+ size_t actualSelection = firstDisplayedItem;
+ int selectY = y_offset;
+ while (selectY + actualItemHeight < startSelection) {
+ selectY += actualItemHeight;
+ actualSelection++;
+ }
+
+ if (actualSelection < GetItemCount())
+ return actualSelection;
+
+ return NO_ITEM;
+}
+
+int GUIScrollList::NotifyTouch(TOUCH_STATE state, int x, int y)
+{
+ if(!isConditionTrue())
+ return -1;
+
+ switch (state)
+ {
+ case TOUCH_START:
+ if (hasScroll && x >= mRenderX + mRenderW - mFastScrollW)
+ fastScroll = 1; // Initial touch is in the fast scroll region
+ if (scrollingSpeed != 0) {
+ selectedItem = NO_ITEM; // this allows the user to tap the list to stop the scrolling without selecting the item they tap
+ scrollingSpeed = 0; // stop scrolling on a new touch
+ } else if (!fastScroll) {
+ // find out which item the user touched
+ selectedItem = HitTestItem(x, y);
+ }
+ if (selectedItem != NO_ITEM)
+ mUpdate = 1;
+ lastY = last2Y = y;
+ break;
+
+ case TOUCH_DRAG:
+ if (fastScroll)
+ {
+ int pct = ((y-mRenderY-mHeaderH)*100)/(mRenderH-mHeaderH);
+ int totalSize = GetItemCount();
+ int lines = GetDisplayItemCount();
+
+ float l = float((totalSize-lines)*pct)/100;
+ if(l + lines >= totalSize)
+ {
+ firstDisplayedItem = totalSize - lines;
+ if (GetDisplayRemainder() != 0) {
+ // There's a partial row displayed, set the scrolling offset so that the last item really is at the very bottom
+ firstDisplayedItem--;
+ y_offset = GetDisplayRemainder() - actualItemHeight;
+ } else {
+ // There's no partial row so zero out the offset
+ y_offset = 0;
+ }
+ }
+ else
+ {
+ if (l < 0)
+ l = 0;
+ firstDisplayedItem = l;
+ y_offset = -(l - int(l))*actualItemHeight;
+ if (GetDisplayRemainder() != 0) {
+ // There's a partial row displayed, make sure y_offset doesn't go past the max
+ if (firstDisplayedItem == totalSize - lines - 1 && y_offset < GetDisplayRemainder() - actualItemHeight)
+ y_offset = GetDisplayRemainder() - actualItemHeight;
+ } else if (firstDisplayedItem == totalSize - lines)
+ y_offset = 0;
+ }
+
+ selectedItem = NO_ITEM;
+ mUpdate = 1;
+ scrollingSpeed = 0; // prevent kinetic scrolling when using fast scroll
+ break;
+ }
+
+ // Provide some debounce on initial touches
+ if (selectedItem != NO_ITEM && abs(y - lastY) < touchDebounce) {
+ mUpdate = 1;
+ break;
+ }
+
+ selectedItem = NO_ITEM; // nothing is selected because we dragged too far
+ // Handle scrolling
+ if (hasScroll) {
+ y_offset += y - lastY; // adjust the scrolling offset based on the difference between the starting touch and the current touch
+ last2Y = lastY; // keep track of previous y locations so that we can tell how fast to scroll for kinetic scrolling
+ lastY = y; // update last touch to the current touch so we can tell how far and what direction we scroll for the next touch event
+
+ HandleScrolling();
+ } else
+ y_offset = 0;
+ mUpdate = 1;
+ break;
+
+ case TOUCH_RELEASE:
+ fastScroll = 0;
+ if (selectedItem != NO_ITEM) {
+ // We've selected an item!
+ NotifySelect(selectedItem);
+ mUpdate = 1;
+
+ DataManager::Vibrate("tw_button_vibrate");
+ selectedItem = NO_ITEM;
+ } else {
+ // Start kinetic scrolling
+ scrollingSpeed = lastY - last2Y;
+ if (abs(scrollingSpeed) > SCROLLING_FLOOR)
+ scrollingSpeed *= SCROLLING_MULTIPLIER;
+ else
+ scrollingSpeed = 0;
+ }
+ case TOUCH_REPEAT:
+ case TOUCH_HOLD:
+ break;
+ }
+ return 0;
+}
+
+void GUIScrollList::HandleScrolling()
+{
+ // handle dragging downward, scrolling upward
+ // the offset should always be <= 0 and > -actualItemHeight, adjust the first display row and offset as needed
+ while(firstDisplayedItem && y_offset > 0) {
+ firstDisplayedItem--;
+ y_offset -= actualItemHeight;
+ }
+ if (firstDisplayedItem == 0 && y_offset > 0)
+ y_offset = 0; // user kept dragging downward past the top of the list, so always reset the offset to 0 since we can't scroll any further in this direction
+
+ // handle dragging upward, scrolling downward
+ int totalSize = GetItemCount();
+ int lines = GetDisplayItemCount(); // number of full lines our list can display at once
+ int bottom_offset = GetDisplayRemainder() - actualItemHeight; // extra display area that can display a partial line for per pixel scrolling
+
+ // the offset should always be <= 0 and > -actualItemHeight, adjust the first display row and offset as needed
+ while (firstDisplayedItem + lines + (bottom_offset ? 1 : 0) < totalSize && abs(y_offset) > actualItemHeight) {
+ firstDisplayedItem++;
+ y_offset += actualItemHeight;
+ }
+ // Check if we dragged too far, set the list at the bottom and adjust offset as needed
+ if (bottom_offset != 0 && firstDisplayedItem + lines + 1 >= totalSize && y_offset <= bottom_offset) {
+ firstDisplayedItem = totalSize - lines - 1;
+ y_offset = bottom_offset;
+ } else if (firstDisplayedItem + lines >= totalSize && y_offset < 0) {
+ firstDisplayedItem = totalSize - lines;
+ y_offset = 0;
+ }
+}
+
+int GUIScrollList::GetDisplayItemCount()
+{
+ return (mRenderH - mHeaderH) / (actualItemHeight);
+}
+
+int GUIScrollList::GetDisplayRemainder()
+{
+ return (mRenderH - mHeaderH) % actualItemHeight;
+}
+
+int GUIScrollList::NotifyVarChange(const std::string& varName, const std::string& value)
+{
+ GUIObject::NotifyVarChange(varName, value);
+
+ if(!isConditionTrue())
+ return 0;
+
+ if (!mHeaderIsStatic) {
+ std::string newValue = gui_parse_text(mHeaderText);
+ if (mLastHeaderValue != newValue) {
+ mLastHeaderValue = newValue;
+ firstDisplayedItem = 0;
+ y_offset = 0;
+ scrollingSpeed = 0; // stop kinetic scrolling on variable changes
+ mUpdate = 1;
+ }
+ }
+ return 0;
+}
+
+int GUIScrollList::SetRenderPos(int x, int y, int w /* = 0 */, int h /* = 0 */)
+{
+ mRenderX = x;
+ mRenderY = y;
+ if (w || h)
+ {
+ mRenderW = w;
+ mRenderH = h;
+ }
+ SetActionPos(mRenderX, mRenderY, mRenderW, mRenderH);
+ mUpdate = 1;
+ return 0;
+}
+
+void GUIScrollList::SetPageFocus(int inFocus)
+{
+ if (inFocus) {
+ NotifyVarChange("", ""); // This forces a check for the header text
+ scrollingSpeed = 0; // stop kinetic scrolling on page changes
+ mUpdate = 1;
+ }
+}