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Qml特效8-进场动画-十字

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简介

这是《Qml特效-进场动画》系列文章的第8篇,涛哥将会教大家一些Qml进场动画相关的知识。

进场动画效果 参考了WPS版ppt的动画,基本效果已经全部实现,可以到github TaoQuick项目中预览:

进场动画预览

关于文章

文章主要发布在涛哥的博客涛哥的知乎专栏-Qt进阶之路

十字效果预览

十字效果,支持由内到外、由外到内两种

实现原理

通过数值动画,控制百分比属性percent从0 到100变化

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import QtQuick 2.12
import QtQuick.Controls 2.12
ShaderEffect {
...
enum Direct {
FromInner = 0,
FromOuter = 1
}
property int dir : ASquare.Direct.FromInner
property int percent: 0
opacity: percent > 0 ? 1 : 0
NumberAnimation {
id: animation
target: r
property: "percent"
from: 0
to: 100
alwaysRunToEnd: true
loops: 1
duration: 1000
}
...
}

在Shader中,使用glsl片段着色器实现像素的控制:

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    fragmentShader: TCommon.fragmentShaderCommon + (dir === ASquare.Direct.FromInner ? "
in vec2 qt_TexCoord0;
uniform float qt_Opacity;
uniform sampler2D effectSource;
uniform int dir;
uniform int percent;
out vec4 fragColor;
void main()
{
vec4 color = texture2D(effectSource, qt_TexCoord0);
float p = float(percent) / 200.0;
float alpha = 0.0;
if ((0.5 - p <= qt_TexCoord0.x && qt_TexCoord0.x <= 0.5 + p) ||
((qt_TexCoord0.x< 0.5 - p || qt_TexCoord0.x > 0.5 + p) && (0.5 - p <= qt_TexCoord0.y && qt_TexCoord0.y < 0.5 + p))
)
{
alpha = 1.0;
}
alpha *= qt_Opacity;
fragColor = vec4(color.rgb * alpha, alpha);
}
" : "
in vec2 qt_TexCoord0;
uniform float qt_Opacity;
uniform sampler2D effectSource;
uniform int dir;
uniform int percent;
out vec4 fragColor;
void main()
{
vec4 color = texture2D(effectSource, qt_TexCoord0);
float p = float(percent) / 200.0;
float alpha = ((1.0 - step(p, qt_TexCoord0.x)) + (step(1.0 - p, qt_TexCoord0.x))) *
((1.0 - step(p, qt_TexCoord0.y)) + (step(1.0 - p, qt_TexCoord0.y)));
alpha = alpha * qt_Opacity;
fragColor = vec4(color.rgb * alpha, alpha);
}
")
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