third_party/WebKit/Source/core/css/cssom/CSSPerspective.cpp

// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "core/css/cssom/CSSPerspective.h"

#include "bindings/core/v8/ExceptionState.h"
#include "core/css/cssom/CSSUnitValue.h"
#include "core/geometry/DOMMatrix.h"

namespace blink {

CSSPerspective* CSSPerspective::Create(CSSNumericValue* length,
                                       ExceptionState& exception_state) {
  if (length->GetType() != CSSStyleValue::StyleValueType::kLengthType) {
    exception_state.ThrowTypeError("Must pass length to CSSPerspective");
    return nullptr;
  }
  if (length->ContainsPercent()) {
    exception_state.ThrowTypeError(
        "CSSPerspective does not support CSSNumericValues with percent units");
    return nullptr;
  }
  return new CSSPerspective(length);
}

void CSSPerspective::setLength(CSSNumericValue* length,
                               ExceptionState& exception_state) {
  if (length->GetType() != CSSStyleValue::StyleValueType::kLengthType) {
    exception_state.ThrowTypeError("Must pass length to CSSPerspective");
    return;
  }
  if (length->ContainsPercent()) {
    exception_state.ThrowTypeError(
        "CSSPerspective does not support CSSNumericValues with percent units");
    return;
  }
  length_ = length;
}

CSSPerspective* CSSPerspective::FromCSSValue(const CSSFunctionValue& value) {
  DCHECK_EQ(value.FunctionType(), CSSValuePerspective);
  DCHECK_EQ(value.length(), 1U);
  CSSNumericValue* length =
      CSSNumericValue::FromCSSValue(ToCSSPrimitiveValue(value.Item(0)));
  // TODO(meade): This shouldn't happen once CSSNumericValue is fully
  // implemented, so once that happens this check can be removed.
  if (!length)
    return nullptr;
  DCHECK(!length->ContainsPercent());
  return new CSSPerspective(length);
}

DOMMatrix* CSSPerspective::AsMatrix() const {
  if (!length_->IsCalculated() && ToCSSUnitValue(length_)->value() < 0) {
    // Negative values are invalid.
    // https://github.com/w3c/css-houdini-drafts/issues/420
    return nullptr;
  }
  CSSUnitValue* length = length_->to(CSSPrimitiveValue::UnitType::kPixels);
  if (!length) {
    // This can happen if there are relative units. TODO(meade): How to resolve
    // relative units here?
    // https://github.com/w3c/css-houdini-drafts/issues/421
    return nullptr;
  }
  DOMMatrix* matrix = DOMMatrix::Create();
  matrix->perspectiveSelf(length->value());
  return matrix;
}

CSSFunctionValue* CSSPerspective::ToCSSValue() const {
  if (!length_->IsCalculated() && ToCSSUnitValue(length_)->value() < 0) {
    // Negative values are invalid.
    // https://github.com/w3c/css-houdini-drafts/issues/420
    return nullptr;
  }
  CSSFunctionValue* result = CSSFunctionValue::Create(CSSValuePerspective);
  result->Append(*length_->ToCSSValue());
  return result;
}

}  // namespace blink