dom/smil/nsSMILCSSProperty.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 /* representation of a SMIL-animatable CSS property on an element */
   7
   8 #include "nsSMILCSSProperty.h"
   9 #include "nsSMILCSSValueType.h"
  10 #include "nsSMILValue.h"
  11 #include "nsComputedDOMStyle.h"
  12 #include "nsCSSProps.h"
  13 #include "mozilla/dom/Element.h"
  14 #include "nsIDOMElement.h"
  15 #include "nsIDocument.h"
  16
  17 using namespace mozilla::dom;
  18
  19 // Helper function
  20 static bool
  21 GetCSSComputedValue(Element* aElem,
  22                     nsCSSProperty aPropID,
  23                     nsAString& aResult)
  24 {
  25   NS_ABORT_IF_FALSE(!nsCSSProps::IsShorthand(aPropID),
  26                     "Can't look up computed value of shorthand property");
  27   NS_ABORT_IF_FALSE(nsSMILCSSProperty::IsPropertyAnimatable(aPropID),
  28                     "Shouldn't get here for non-animatable properties");
  29
  30   nsIDocument* doc = aElem->GetCurrentDoc();
  31   if (!doc) {
  32     // This can happen if we process certain types of restyles mid-sample
  33     // and remove anonymous animated content from the document as a result.
  34     // See bug 534975.
  35     return false;
  36   }
  37
  38   nsIPresShell* shell = doc->GetShell();
  39   if (!shell) {
  40     NS_WARNING("Unable to look up computed style -- no pres shell");
  41     return false;
  42   }
  43
  44   nsRefPtr<nsComputedDOMStyle> computedStyle =
  45     NS_NewComputedDOMStyle(aElem, EmptyString(), shell);
  46
  47   computedStyle->GetPropertyValue(aPropID, aResult);
  48   return true;
  49 }
  50
  51 // Class Methods
  52 nsSMILCSSProperty::nsSMILCSSProperty(nsCSSProperty aPropID,
  53                                      Element* aElement)
  54   : mPropID(aPropID), mElement(aElement)
  55 {
  56   NS_ABORT_IF_FALSE(IsPropertyAnimatable(mPropID),
  57                     "Creating a nsSMILCSSProperty for a property "
  58                     "that's not supported for animation");
  59 }
  60
  61 nsSMILValue
  62 nsSMILCSSProperty::GetBaseValue() const
  63 {
  64   // To benefit from Return Value Optimization and avoid copy constructor calls
  65   // due to our use of return-by-value, we must return the exact same object
  66   // from ALL return points. This function must only return THIS variable:
  67   nsSMILValue baseValue;
  68
  69   // SPECIAL CASE: (a) Shorthands
  70   //               (b) 'display'
  71   if (nsCSSProps::IsShorthand(mPropID) || mPropID == eCSSProperty_display) {
  72     // We can't look up the base (computed-style) value of shorthand
  73     // properties because they aren't guaranteed to have a consistent computed
  74     // value.
  75     //
  76     // Also, although we can look up the base value of the display property,
  77     // doing so involves clearing and resetting the property which can cause
  78     // frames to be recreated which we'd like to avoid.
  79     //
  80     // In either case, just return a dummy value (initialized with the right
  81     // type, so as not to indicate failure).
  82     nsSMILValue tmpVal(&nsSMILCSSValueType::sSingleton);
  83     baseValue.Swap(tmpVal);
  84     return baseValue;
  85   }
  86
  87   // GENERAL CASE: Non-Shorthands
  88   // (1) Put empty string in override style for property mPropID
  89   // (saving old override style value, so we can set it again when we're done)
  90   nsICSSDeclaration* overrideDecl = mElement->GetSMILOverrideStyle();
  91   nsAutoString cachedOverrideStyleVal;
  92   if (overrideDecl) {
  93     overrideDecl->GetPropertyValue(mPropID, cachedOverrideStyleVal);
  94     // (Don't bother clearing override style if it's already empty)
  95     if (!cachedOverrideStyleVal.IsEmpty()) {
  96       overrideDecl->SetPropertyValue(mPropID, EmptyString());
  97     }
  98   }
  99
 100   // (2) Get Computed Style
 101   nsAutoString computedStyleVal;
 102   bool didGetComputedVal = GetCSSComputedValue(mElement, mPropID,
 103                                                  computedStyleVal);
 104
 105   // (3) Put cached override style back (if it's non-empty)
 106   if (overrideDecl && !cachedOverrideStyleVal.IsEmpty()) {
 107     overrideDecl->SetPropertyValue(mPropID, cachedOverrideStyleVal);
 108   }
 109
 110   // (4) Populate our nsSMILValue from the computed style
 111   if (didGetComputedVal) {
 112     // When we parse animation values we check if they are context-sensitive or
 113     // not so that we don't cache animation values whose meaning may change.
 114     // For base values however this is unnecessary since on each sample the
 115     // compositor will fetch the (computed) base value and compare it against
 116     // the cached (computed) value and detect changes for us.
 117     nsSMILCSSValueType::ValueFromString(mPropID, mElement,
 118                                         computedStyleVal, baseValue,
 119                                         nullptr);
 120   }
 121   return baseValue;
 122 }
 123
 124 nsresult
 125 nsSMILCSSProperty::ValueFromString(const nsAString& aStr,
 126                                    const SVGAnimationElement* aSrcElement,
 127                                    nsSMILValue& aValue,
 128                                    bool& aPreventCachingOfSandwich) const
 129 {
 130   NS_ENSURE_TRUE(IsPropertyAnimatable(mPropID), NS_ERROR_FAILURE);
 131
 132   nsSMILCSSValueType::ValueFromString(mPropID, mElement, aStr, aValue,
 133       &aPreventCachingOfSandwich);
 134
 135   if (aValue.IsNull()) {
 136     return NS_ERROR_FAILURE;
 137   }
 138
 139   // XXX Due to bug 536660 (or at least that seems to be the most likely
 140   // culprit), when we have animation setting display:none on a <use> element,
 141   // if we DON'T set the property every sample, chaos ensues.
 142   if (!aPreventCachingOfSandwich && mPropID == eCSSProperty_display) {
 143     aPreventCachingOfSandwich = true;
 144   }
 145   return NS_OK;
 146 }
 147
 148 nsresult
 149 nsSMILCSSProperty::SetAnimValue(const nsSMILValue& aValue)
 150 {
 151   NS_ENSURE_TRUE(IsPropertyAnimatable(mPropID), NS_ERROR_FAILURE);
 152
 153   // Convert nsSMILValue to string
 154   nsAutoString valStr;
 155   if (!nsSMILCSSValueType::ValueToString(aValue, valStr)) {
 156     NS_WARNING("Failed to convert nsSMILValue for CSS property into a string");
 157     return NS_ERROR_FAILURE;
 158   }
 159
 160   // Use string value to style the target element
 161   nsICSSDeclaration* overrideDecl = mElement->GetSMILOverrideStyle();
 162   if (overrideDecl) {
 163     nsAutoString oldValStr;
 164     overrideDecl->GetPropertyValue(mPropID, oldValStr);
 165     if (valStr.Equals(oldValStr)) {
 166       return NS_OK;
 167     }
 168     overrideDecl->SetPropertyValue(mPropID, valStr);
 169   }
 170   return NS_OK;
 171 }
 172
 173 void
 174 nsSMILCSSProperty::ClearAnimValue()
 175 {
 176   // Put empty string in override style for our property
 177   nsICSSDeclaration* overrideDecl = mElement->GetSMILOverrideStyle();
 178   if (overrideDecl) {
 179     overrideDecl->SetPropertyValue(mPropID, EmptyString());
 180   }
 181 }
 182
 183 // Based on http://www.w3.org/TR/SVG/propidx.html
 184 // static
 185 bool
 186 nsSMILCSSProperty::IsPropertyAnimatable(nsCSSProperty aPropID)
 187 {
 188   // NOTE: Right now, Gecko doesn't recognize the following properties from
 189   // the SVG Property Index:
 190   //   alignment-baseline
 191   //   baseline-shift
 192   //   color-profile
 193   //   color-rendering
 194   //   glyph-orientation-horizontal
 195   //   glyph-orientation-vertical
 196   //   kerning
 197   //   writing-mode
 198
 199   switch (aPropID) {
 200     case eCSSProperty_clip:
 201     case eCSSProperty_clip_rule:
 202     case eCSSProperty_clip_path:
 203     case eCSSProperty_color:
 204     case eCSSProperty_color_interpolation:
 205     case eCSSProperty_color_interpolation_filters:
 206     case eCSSProperty_cursor:
 207     case eCSSProperty_display:
 208     case eCSSProperty_dominant_baseline:
 209     case eCSSProperty_fill:
 210     case eCSSProperty_fill_opacity:
 211     case eCSSProperty_fill_rule:
 212     case eCSSProperty_filter:
 213     case eCSSProperty_flood_color:
 214     case eCSSProperty_flood_opacity:
 215     case eCSSProperty_font:
 216     case eCSSProperty_font_family:
 217     case eCSSProperty_font_size:
 218     case eCSSProperty_font_size_adjust:
 219     case eCSSProperty_font_stretch:
 220     case eCSSProperty_font_style:
 221     case eCSSProperty_font_variant:
 222     case eCSSProperty_font_weight:
 223     case eCSSProperty_height:
 224     case eCSSProperty_image_rendering:
 225     case eCSSProperty_letter_spacing:
 226     case eCSSProperty_lighting_color:
 227     case eCSSProperty_marker:
 228     case eCSSProperty_marker_end:
 229     case eCSSProperty_marker_mid:
 230     case eCSSProperty_marker_start:
 231     case eCSSProperty_mask:
 232     case eCSSProperty_mask_type:
 233     case eCSSProperty_opacity:
 234     case eCSSProperty_overflow:
 235     case eCSSProperty_pointer_events:
 236     case eCSSProperty_shape_rendering:
 237     case eCSSProperty_stop_color:
 238     case eCSSProperty_stop_opacity:
 239     case eCSSProperty_stroke:
 240     case eCSSProperty_stroke_dasharray:
 241     case eCSSProperty_stroke_dashoffset:
 242     case eCSSProperty_stroke_linecap:
 243     case eCSSProperty_stroke_linejoin:
 244     case eCSSProperty_stroke_miterlimit:
 245     case eCSSProperty_stroke_opacity:
 246     case eCSSProperty_stroke_width:
 247     case eCSSProperty_text_anchor:
 248     case eCSSProperty_text_decoration:
 249     case eCSSProperty_text_decoration_line:
 250     case eCSSProperty_text_rendering:
 251     case eCSSProperty_vector_effect:
 252     case eCSSProperty_width:
 253     case eCSSProperty_visibility:
 254     case eCSSProperty_word_spacing:
 255       return true;
 256
 257     // EXPLICITLY NON-ANIMATABLE PROPERTIES:
 258     // (Some of these aren't supported at all in Gecko -- I've commented those
 259     // ones out. If/when we add support for them, uncomment their line here)
 260     // ----------------------------------------------------------------------
 261     // case eCSSProperty_enable_background:
 262     // case eCSSProperty_glyph_orientation_horizontal:
 263     // case eCSSProperty_glyph_orientation_vertical:
 264     // case eCSSProperty_writing_mode:
 265     case eCSSProperty_direction:
 266     case eCSSProperty_unicode_bidi:
 267       return false;
 268
 269     default:
 270       return false;
 271   }
 272 }