dali-toolkit/devel-api/shader-effects/nine-patch-mask-effect.h

   1 #ifndef __DALI_TOOLKIT_NINE_PATCH_MASK_EFFECT_H__
   2 #define __DALI_TOOLKIT_NINE_PATCH_MASK_EFFECT_H__
   3
   4 /*
   5  * Copyright (c) 2015 Samsung Electronics Co., Ltd.
   6  *
   7  * Licensed under the Apache License, Version 2.0 (the "License");
   8  * you may not use this file except in compliance with the License.
   9  * You may obtain a copy of the License at
  10  *
  11  * http://www.apache.org/licenses/LICENSE-2.0
  12  *
  13  * Unless required by applicable law or agreed to in writing, software
  14  * distributed under the License is distributed on an "AS IS" BASIS,
  15  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  16  * See the License for the specific language governing permissions and
  17  * limitations under the License.
  18  *
  19  */
  20
  21 // EXTERNAL INCLUDES
  22 #include <dali/public-api/actors/image-actor.h>
  23
  24 namespace Dali
  25 {
  26
  27 namespace Toolkit
  28 {
  29
  30 /**
  31  * @brief NinePatchMaskEffect is used to control which parts of an image are visible, using the alpha channel of a separate mask image.
  32  *
  33  * The mask image is expected to be smaller than the main image being viewed.
  34  * Conceptually the mask image is divided into a 3x3 grid (9 patches). The middle patch is stretched whilst the outer border is not.
  35  *
  36  * Usage example:
  37  *
  38  * @code
  39  *   ImageActor actor = ImageActor::New( Image( EXAMPLE_IMAGE_PATH ) );
  40  *   NinePatchMaskEffect::Apply( actor, MASK_IMAGE_PATH );
  41  * @endcode
  42  *
  43  * NinePatchMaskEffect is mutually exclusive with ImageActor::STYLE_NINE_PATCH i.e. the actor's main image should not be a nine-patch.
  44  */
  45 namespace NinePatchMaskEffect
  46 {
  47
  48 static void NinePatchMaskEffectSizeConstraint( Vector2& current, const PropertyInputContainer& inputs )
  49 {
  50   const Vector3& actorSize = inputs[0]->GetVector3();
  51   current.x = actorSize.x;
  52   current.y = actorSize.y;
  53 }
  54
  55 inline void DoApply( ImageActor actor, const std::string& maskImage, const Vector2& maskSize, Vector4 maskBorder )
  56 {
  57   const char* ALPHA_MASK_VERTEX_SHADER_SOURCE =
  58   "precision mediump float;\n"
  59   "uniform vec2 uImageSize;                                                       \n"
  60   "uniform vec2 uMaskSize;                                                        \n"
  61   "varying vec2 vMaskTexCoord;                                                    \n"
  62   "                                                                               \n"
  63   "void main()                                                                    \n"
  64   "{                                                                              \n"
  65   "  gl_Position = uMvpMatrix * vec4(aPosition, 1.0);                             \n"
  66   "                                                                               \n"
  67   "  // Ignore mask UVs for image                                                 \n"
  68   "                                                                               \n"
  69   "  highp vec2 halfImageSize = uImageSize * 0.5;                                 \n"
  70   "  vTexCoord = (aPosition.xy + halfImageSize) / uImageSize;                     \n"
  71   "                                                                               \n"
  72   "  // UVs were calculated for image size, so convert for mask size              \n"
  73   "                                                                               \n"
  74   "  highp vec2 halfMaskSize  = uMaskSize * 0.5;                                  \n"
  75   "  highp vec2 halfSizeDelta = halfImageSize - halfMaskSize;                     \n"
  76   "                                                                               \n"
  77   "  highp vec2 maskPosition = aPosition.xy;                                      \n"
  78   "  maskPosition.x -= halfSizeDelta.x * sign(aPosition.x);                       \n"
  79   "  maskPosition.y -= halfSizeDelta.y * sign(aPosition.y);                       \n"
  80   "                                                                               \n"
  81   "  vMaskTexCoord = (maskPosition + halfMaskSize) / uMaskSize;                   \n"
  82   "}                                                                              \n";
  83
  84   const char* ALPHA_MASK_FRAGMENT_SHADER_SOURCE =
  85   "varying mediump vec2 vMaskTexCoord;                                            \n"
  86   "                                                                               \n"
  87   "void main()                                                                    \n"
  88   "{                                                                              \n"
  89   "  highp vec4 mask = texture2D(sEffect, vMaskTexCoord);                         \n"
  90   "  gl_FragColor = texture2D(sTexture, vTexCoord) * uColor * vec4(1,1,1,mask.a); \n"
  91   "}                                                                              \n";
  92
  93   ShaderEffect maskEffect = ShaderEffect::New(
  94     ALPHA_MASK_VERTEX_SHADER_SOURCE,
  95     ALPHA_MASK_FRAGMENT_SHADER_SOURCE,
  96     ShaderEffect::GeometryHints( ShaderEffect::HINT_BLENDING ) );
  97
  98   maskEffect.SetEffectImage( ResourceImage::New( maskImage ) );
  99
 100   maskEffect.SetUniform( "uImageSize", Vector2(0,0) /*Constrained to actor size*/ );
 101
 102   Constraint constraint = Constraint::New<Vector2>( maskEffect, maskEffect.GetPropertyIndex("uImageSize"), NinePatchMaskEffectSizeConstraint );
 103   constraint.AddSource( Source(actor, Actor::Property::SIZE) );
 104   constraint.Apply();
 105
 106   maskEffect.SetUniform( "uMaskSize", maskSize );
 107
 108   // Actor must provide nine-patch style geometry for this effect to work
 109   actor.SetStyle( ImageActor::STYLE_NINE_PATCH );
 110   actor.SetNinePatchBorder( maskBorder );
 111
 112   actor.SetShaderEffect( maskEffect );
 113 }
 114
 115 /**
 116  * @brief Apply the mask effect to an ImageActor.
 117  *
 118  * NinePatchMaskEffect is mutually exclusive with ImageActor::STYLE_NINE_PATCH i.e. the actor's main image should not be a nine-patch.
 119  * @param [in] actor The actor which needs the effect. To remove the effect call actor.RemoveShaderEffect().
 120  * @param [in] maskImage The path to a file containing the mask. The center pixels of the mask will be stretched.
 121  */
 122 inline void Apply( ImageActor actor, const std::string& maskImage )
 123 {
 124   const Uint16Pair maskSize = ResourceImage::GetImageSize( maskImage );
 125
 126   const float leftRight = (maskSize.GetWidth()  - 1.0f) * 0.5f;
 127   const float topBottom = (maskSize.GetHeight() - 1.0f) * 0.5f;
 128
 129   DoApply( actor, maskImage, Vector2( maskSize.GetWidth(), maskSize.GetHeight() ), Vector4( leftRight, topBottom, leftRight, topBottom ) );
 130 }
 131
 132 /**
 133  * @brief Apply the mask effect to an ImageActor.
 134  *
 135  * NinePatchMaskEffect is mutually exclusive with ImageActor::STYLE_NINE_PATCH i.e. the actor's main image should not be a nine-patch.
 136  * @param [in] actor The actor which needs the effect. To remove the effect call actor.RemoveShaderEffect().
 137  * @param [in] maskImage The path to a file containing the mask.
 138  * @param [in] maskBorder Specifies the part of the mask image that will be stretched (left, top, right, bottom).
 139  */
 140 inline void Apply( ImageActor actor, const std::string& maskImage, const Vector4& maskBorder )
 141 {
 142   const Uint16Pair maskSize = ResourceImage::GetImageSize( maskImage );
 143
 144   DoApply( actor, maskImage, Vector2( maskSize.GetWidth(), maskSize.GetHeight() ), maskBorder );
 145 }
 146
 147 } // namespace NinePatchMaskEffect
 148
 149 } // namespace Toolkit
 150
 151 } // namespace Dali
 152
 153 #endif // __DALI_TOOLKIT_NINE_PATCH_MASK_EFFECT_H__