layout/xul/nsStackLayout.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 //
   7 // Eric Vaughan
   8 // Netscape Communications
   9 //
  10 // See documentation in associated header file
  11 //
  12
  13 #include "nsStackLayout.h"
  14 #include "nsCOMPtr.h"
  15 #include "nsBoxLayoutState.h"
  16 #include "nsBox.h"
  17 #include "nsBoxFrame.h"
  18 #include "nsGkAtoms.h"
  19 #include "nsIContent.h"
  20 #include "nsNameSpaceManager.h"
  21
  22 using namespace mozilla;
  23
  24 nsBoxLayout* nsStackLayout::gInstance = nullptr;
  25
  26 #define SPECIFIED_LEFT (1 << NS_SIDE_LEFT)
  27 #define SPECIFIED_RIGHT (1 << NS_SIDE_RIGHT)
  28 #define SPECIFIED_TOP (1 << NS_SIDE_TOP)
  29 #define SPECIFIED_BOTTOM (1 << NS_SIDE_BOTTOM)
  30
  31 nsresult
  32 NS_NewStackLayout( nsIPresShell* aPresShell, nsCOMPtr<nsBoxLayout>& aNewLayout)
  33 {
  34   if (!nsStackLayout::gInstance) {
  35     nsStackLayout::gInstance = new nsStackLayout();
  36     NS_IF_ADDREF(nsStackLayout::gInstance);
  37   }
  38   // we have not instance variables so just return our static one.
  39   aNewLayout = nsStackLayout::gInstance;
  40   return NS_OK;
  41 }
  42
  43 /*static*/ void
  44 nsStackLayout::Shutdown()
  45 {
  46   NS_IF_RELEASE(gInstance);
  47 }
  48
  49 nsStackLayout::nsStackLayout()
  50 {
  51 }
  52
  53 /*
  54  * Sizing: we are as wide as the widest child plus its left offset
  55  * we are tall as the tallest child plus its top offset.
  56  *
  57  * Only children which have -moz-stack-sizing set to stretch-to-fit
  58  * (the default) will be included in the size computations.
  59  */
  60
  61 nsSize
  62 nsStackLayout::GetPrefSize(nsIFrame* aBox, nsBoxLayoutState& aState)
  63 {
  64   nsSize prefSize (0, 0);
  65
  66   nsIFrame* child = nsBox::GetChildBox(aBox);
  67   while (child) {
  68     if (child->StyleXUL()->mStretchStack) {
  69       nsSize pref = child->GetPrefSize(aState);
  70
  71       AddMargin(child, pref);
  72       nsMargin offset;
  73       GetOffset(aState, child, offset);
  74       pref.width += offset.LeftRight();
  75       pref.height += offset.TopBottom();
  76       AddLargestSize(prefSize, pref);
  77     }
  78
  79     child = nsBox::GetNextBox(child);
  80   }
  81
  82   AddBorderAndPadding(aBox, prefSize);
  83
  84   return prefSize;
  85 }
  86
  87 nsSize
  88 nsStackLayout::GetMinSize(nsIFrame* aBox, nsBoxLayoutState& aState)
  89 {
  90   nsSize minSize (0, 0);
  91
  92   nsIFrame* child = nsBox::GetChildBox(aBox);
  93   while (child) {
  94     if (child->StyleXUL()->mStretchStack) {
  95       nsSize min = child->GetMinSize(aState);
  96
  97       AddMargin(child, min);
  98       nsMargin offset;
  99       GetOffset(aState, child, offset);
 100       min.width += offset.LeftRight();
 101       min.height += offset.TopBottom();
 102       AddLargestSize(minSize, min);
 103     }
 104
 105     child = nsBox::GetNextBox(child);
 106   }
 107
 108   AddBorderAndPadding(aBox, minSize);
 109
 110   return minSize;
 111 }
 112
 113 nsSize
 114 nsStackLayout::GetMaxSize(nsIFrame* aBox, nsBoxLayoutState& aState)
 115 {
 116   nsSize maxSize (NS_INTRINSICSIZE, NS_INTRINSICSIZE);
 117
 118   nsIFrame* child = nsBox::GetChildBox(aBox);
 119   while (child) {
 120     if (child->StyleXUL()->mStretchStack) {
 121       nsSize min = child->GetMinSize(aState);
 122       nsSize max = child->GetMaxSize(aState);
 123
 124       max = nsBox::BoundsCheckMinMax(min, max);
 125
 126       AddMargin(child, max);
 127       nsMargin offset;
 128       GetOffset(aState, child, offset);
 129       max.width += offset.LeftRight();
 130       max.height += offset.TopBottom();
 131       AddSmallestSize(maxSize, max);
 132     }
 133
 134     child = nsBox::GetNextBox(child);
 135   }
 136
 137   AddBorderAndPadding(aBox, maxSize);
 138
 139   return maxSize;
 140 }
 141
 142
 143 nscoord
 144 nsStackLayout::GetAscent(nsIFrame* aBox, nsBoxLayoutState& aState)
 145 {
 146   nscoord vAscent = 0;
 147
 148   nsIFrame* child = nsBox::GetChildBox(aBox);
 149   while (child) {
 150     nscoord ascent = child->GetBoxAscent(aState);
 151     nsMargin margin;
 152     child->GetMargin(margin);
 153     ascent += margin.top;
 154     if (ascent > vAscent)
 155       vAscent = ascent;
 156
 157     child = nsBox::GetNextBox(child);
 158   }
 159
 160   return vAscent;
 161 }
 162
 163 uint8_t
 164 nsStackLayout::GetOffset(nsBoxLayoutState& aState, nsIFrame* aChild, nsMargin& aOffset)
 165 {
 166   aOffset = nsMargin(0, 0, 0, 0);
 167
 168   // get the left, right, top and bottom offsets
 169
 170   // As an optimization, we cache the fact that we are not positioned to avoid
 171   // wasting time fetching attributes.
 172   if (aChild->IsBoxFrame() &&
 173       (aChild->GetStateBits() & NS_STATE_STACK_NOT_POSITIONED))
 174     return 0;
 175
 176   uint8_t offsetSpecified = 0;
 177   nsIContent* content = aChild->GetContent();
 178   if (content) {
 179     bool ltr = aChild->StyleVisibility()->mDirection == NS_STYLE_DIRECTION_LTR;
 180     nsAutoString value;
 181     nsresult error;
 182
 183     content->GetAttr(kNameSpaceID_None, nsGkAtoms::start, value);
 184     if (!value.IsEmpty()) {
 185       value.Trim("%");
 186       if (ltr) {
 187         aOffset.left =
 188           nsPresContext::CSSPixelsToAppUnits(value.ToInteger(&error));
 189         offsetSpecified |= SPECIFIED_LEFT;
 190       } else {
 191         aOffset.right =
 192           nsPresContext::CSSPixelsToAppUnits(value.ToInteger(&error));
 193         offsetSpecified |= SPECIFIED_RIGHT;
 194       }
 195     }
 196
 197     content->GetAttr(kNameSpaceID_None, nsGkAtoms::end, value);
 198     if (!value.IsEmpty()) {
 199       value.Trim("%");
 200       if (ltr) {
 201         aOffset.right =
 202           nsPresContext::CSSPixelsToAppUnits(value.ToInteger(&error));
 203         offsetSpecified |= SPECIFIED_RIGHT;
 204       } else {
 205         aOffset.left =
 206           nsPresContext::CSSPixelsToAppUnits(value.ToInteger(&error));
 207         offsetSpecified |= SPECIFIED_LEFT;
 208       }
 209     }
 210
 211     content->GetAttr(kNameSpaceID_None, nsGkAtoms::left, value);
 212     if (!value.IsEmpty()) {
 213       value.Trim("%");
 214       aOffset.left =
 215         nsPresContext::CSSPixelsToAppUnits(value.ToInteger(&error));
 216       offsetSpecified |= SPECIFIED_LEFT;
 217     }
 218
 219     content->GetAttr(kNameSpaceID_None, nsGkAtoms::right, value);
 220     if (!value.IsEmpty()) {
 221       value.Trim("%");
 222       aOffset.right =
 223         nsPresContext::CSSPixelsToAppUnits(value.ToInteger(&error));
 224       offsetSpecified |= SPECIFIED_RIGHT;
 225     }
 226
 227     content->GetAttr(kNameSpaceID_None, nsGkAtoms::top, value);
 228     if (!value.IsEmpty()) {
 229       value.Trim("%");
 230       aOffset.top =
 231         nsPresContext::CSSPixelsToAppUnits(value.ToInteger(&error));
 232       offsetSpecified |= SPECIFIED_TOP;
 233     }
 234
 235     content->GetAttr(kNameSpaceID_None, nsGkAtoms::bottom, value);
 236     if (!value.IsEmpty()) {
 237       value.Trim("%");
 238       aOffset.bottom =
 239         nsPresContext::CSSPixelsToAppUnits(value.ToInteger(&error));
 240       offsetSpecified |= SPECIFIED_BOTTOM;
 241     }
 242   }
 243
 244   if (!offsetSpecified && aChild->IsBoxFrame()) {
 245     // If no offset was specified at all, then we cache this fact to avoid requerying
 246     // CSS or the content model.
 247     aChild->AddStateBits(NS_STATE_STACK_NOT_POSITIONED);
 248   }
 249
 250   return offsetSpecified;
 251 }
 252
 253
 254 NS_IMETHODIMP
 255 nsStackLayout::Layout(nsIFrame* aBox, nsBoxLayoutState& aState)
 256 {
 257   nsRect clientRect;
 258   aBox->GetClientRect(clientRect);
 259
 260   bool grow;
 261
 262   do {
 263     nsIFrame* child = nsBox::GetChildBox(aBox);
 264     grow = false;
 265
 266     while (child)
 267     {
 268       nsMargin margin;
 269       child->GetMargin(margin);
 270       nsRect childRect(clientRect);
 271       childRect.Deflate(margin);
 272
 273       if (childRect.width < 0)
 274         childRect.width = 0;
 275
 276       if (childRect.height < 0)
 277         childRect.height = 0;
 278
 279       nsRect oldRect(child->GetRect());
 280       bool sizeChanged = !oldRect.IsEqualEdges(childRect);
 281
 282       // only lay out dirty children or children whose sizes have changed
 283       if (sizeChanged || NS_SUBTREE_DIRTY(child)) {
 284           // add in the child's margin
 285           nsMargin margin;
 286           child->GetMargin(margin);
 287
 288           // obtain our offset from the top left border of the stack's content box.
 289           nsMargin offset;
 290           uint8_t offsetSpecified = GetOffset(aState, child, offset);
 291
 292           // Set the position and size based on which offsets have been specified:
 293           //   left only - offset from left edge, preferred width
 294           //   right only - offset from right edge, preferred width
 295           //   left and right - offset from left and right edges, width in between this
 296           //   neither - no offset, full width of stack
 297           // Vertical direction is similar.
 298           //
 299           // Margins on the child are also included in the edge offsets
 300           if (offsetSpecified) {
 301             if (offsetSpecified & SPECIFIED_LEFT) {
 302               childRect.x = clientRect.x + offset.left + margin.left;
 303               if (offsetSpecified & SPECIFIED_RIGHT) {
 304                 nsSize min = child->GetMinSize(aState);
 305                 nsSize max = child->GetMaxSize(aState);
 306                 nscoord width = clientRect.width - offset.LeftRight() - margin.LeftRight();
 307                 childRect.width = clamped(width, min.width, max.width);
 308               }
 309               else {
 310                 childRect.width = child->GetPrefSize(aState).width;
 311               }
 312             }
 313             else if (offsetSpecified & SPECIFIED_RIGHT) {
 314               childRect.width = child->GetPrefSize(aState).width;
 315               childRect.x = clientRect.XMost() - offset.right - margin.right - childRect.width;
 316             }
 317
 318             if (offsetSpecified & SPECIFIED_TOP) {
 319               childRect.y = clientRect.y + offset.top + margin.top;
 320               if (offsetSpecified & SPECIFIED_BOTTOM) {
 321                 nsSize min = child->GetMinSize(aState);
 322                 nsSize max = child->GetMaxSize(aState);
 323                 nscoord height = clientRect.height - offset.TopBottom() - margin.TopBottom();
 324                 childRect.height = clamped(height, min.height, max.height);
 325               }
 326               else {
 327                 childRect.height = child->GetPrefSize(aState).height;
 328               }
 329             }
 330             else if (offsetSpecified & SPECIFIED_BOTTOM) {
 331               childRect.height = child->GetPrefSize(aState).height;
 332               childRect.y = clientRect.YMost() - offset.bottom - margin.bottom - childRect.height;
 333             }
 334           }
 335
 336           // Now place the child.
 337           child->SetBounds(aState, childRect);
 338
 339           // Flow the child.
 340           child->Layout(aState);
 341
 342           // Get the child's new rect.
 343           childRect = child->GetRect();
 344           childRect.Inflate(margin);
 345
 346           if (child->StyleXUL()->mStretchStack) {
 347             // Did the child push back on us and get bigger?
 348             if (offset.LeftRight() + childRect.width > clientRect.width) {
 349               clientRect.width = childRect.width + offset.LeftRight();
 350               grow = true;
 351             }
 352
 353             if (offset.TopBottom() + childRect.height > clientRect.height) {
 354               clientRect.height = childRect.height + offset.TopBottom();
 355               grow = true;
 356             }
 357           }
 358        }
 359
 360        child = nsBox::GetNextBox(child);
 361      }
 362    } while (grow);
 363
 364    // if some HTML inside us got bigger we need to force ourselves to
 365    // get bigger
 366    nsRect bounds(aBox->GetRect());
 367    nsMargin bp;
 368    aBox->GetBorderAndPadding(bp);
 369    clientRect.Inflate(bp);
 370
 371    if (clientRect.width > bounds.width || clientRect.height > bounds.height)
 372    {
 373      if (clientRect.width > bounds.width)
 374        bounds.width = clientRect.width;
 375      if (clientRect.height > bounds.height)
 376        bounds.height = clientRect.height;
 377
 378      aBox->SetBounds(aState, bounds);
 379    }
 380
 381    return NS_OK;
 382 }
 383