Question

我将三个UIImages添加到三个UIScrollviews中，这三个UIScrollviews一个位于另一个之下。我试图找到一种方法来模糊两个scrollviews之间的相邻边缘，但我无法找到一种方法。

有人可以建议一种方法来实现这一目标吗？

任何帮助将不胜感激

谢谢

Shumais Ul Haq

Answer 1

你可以在图像上做一些高斯模糊。这被问到before。

static void blur(V2fT2f *quad, float t) // t = 1
{
    GLint tex;
    V2fT2f tmpquad[4];
    float offw = t / Input.wide;
    float offh = t / Input.high;
    int i;

    glGetIntegerv(GL_TEXTURE_BINDING_2D, &tex);

    // Three pass small blur, using rotated pattern to sample 17 texels:
    //
    // .\/.. 
    // ./\\/ 
    // \/X/\   rotated samples filter across texel corners
    // /\\/. 
    // ../\. 

    // Pass one: center nearest sample
    glVertexPointer  (2, GL_FLOAT, sizeof(V2fT2f), &quad[0].x);
    glTexCoordPointer(2, GL_FLOAT, sizeof(V2fT2f), &quad[0].s);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE);
    glColor4f(1.0/5, 1.0/5, 1.0/5, 1.0);
    validateTexEnv();
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

    // Pass two: accumulate two rotated linear samples
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glEnable(GL_BLEND);
    glBlendFunc(GL_SRC_ALPHA, GL_ONE);
    for (i = 0; i < 4; i++)
    {
        tmpquad[i].x = quad[i].s + 1.5 * offw;
        tmpquad[i].y = quad[i].t + 0.5 * offh;
        tmpquad[i].s = quad[i].s - 1.5 * offw;
        tmpquad[i].t = quad[i].t - 0.5 * offh;
    }
    glTexCoordPointer(2, GL_FLOAT, sizeof(V2fT2f), &tmpquad[0].x);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_REPLACE);
    glActiveTexture(GL_TEXTURE1);
    glEnable(GL_TEXTURE_2D);
    glClientActiveTexture(GL_TEXTURE1);
    glTexCoordPointer(2, GL_FLOAT, sizeof(V2fT2f), &tmpquad[0].s);
    glEnableClientState(GL_TEXTURE_COORD_ARRAY);
    glBindTexture(GL_TEXTURE_2D, tex);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE);
    glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB,      GL_INTERPOLATE);
    glTexEnvi(GL_TEXTURE_ENV, GL_SRC0_RGB,         GL_TEXTURE);
    glTexEnvi(GL_TEXTURE_ENV, GL_SRC1_RGB,         GL_PREVIOUS);
    glTexEnvi(GL_TEXTURE_ENV, GL_SRC2_RGB,         GL_PRIMARY_COLOR);
    glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND2_RGB,     GL_SRC_COLOR);
    glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_ALPHA,    GL_REPLACE);
    glTexEnvi(GL_TEXTURE_ENV, GL_SRC0_ALPHA,       GL_PRIMARY_COLOR);

    glColor4f(0.5, 0.5, 0.5, 2.0/5);
    validateTexEnv();
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

    // Pass three: accumulate two rotated linear samples
    for (i = 0; i < 4; i++)
    {
        tmpquad[i].x = quad[i].s - 0.5 * offw;
        tmpquad[i].y = quad[i].t + 1.5 * offh;
        tmpquad[i].s = quad[i].s + 0.5 * offw;
        tmpquad[i].t = quad[i].t - 1.5 * offh;
    }
    glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);

    // Restore state
    glDisableClientState(GL_TEXTURE_COORD_ARRAY);
    glClientActiveTexture(GL_TEXTURE0);
    glBindTexture(GL_TEXTURE_2D, Half.texID);
    glDisable(GL_TEXTURE_2D);
    glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND2_RGB,     GL_SRC_ALPHA);
    glActiveTexture(GL_TEXTURE0);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glDisable(GL_BLEND);
}

Answer 2

您可以使用CALayer.mask设置“遮罩层”以添加透明区域。在滚动视图（例如#import <QuartzCore/CALayer.h> ... scrollView.layer.mask = whatever）上设置此项以使边缘更加透明。

我不记得是否自动调整图层蒙版的大小。它们在较旧（例如3G）设备上的表现也特别差。不过，它可能会做你想做的事。

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