• <ins id="pjuwb"></ins>
    <blockquote id="pjuwb"><pre id="pjuwb"></pre></blockquote>
    <noscript id="pjuwb"></noscript>
          <sup id="pjuwb"><pre id="pjuwb"></pre></sup>
            <dd id="pjuwb"></dd>
            <abbr id="pjuwb"></abbr>

            S.l.e!ep.¢%

            像打了激速一樣,以四倍的速度運轉(zhuǎn),開心的工作
            簡單、開放、平等的公司文化;尊重個性、自由與個人價值;
            posts - 1098, comments - 335, trackbacks - 0, articles - 1
              C++博客 :: 首頁 :: 新隨筆 :: 聯(lián)系 :: 聚合  :: 管理

            BLENDFUNCTION

            Posted on 2010-09-07 14:39 S.l.e!ep.¢% 閱讀(924) 評論(1)  編輯 收藏 引用 所屬分類: DirectUI

            typedef struct _BLENDFUNCTION {
            ? BYTE BlendOp;
            ? BYTE BlendFlags;
            ? BYTE SourceConstantAlpha;
            ? BYTE AlphaFormat;
            } BLENDFUNCTION, *PBLENDFUNCTION, *LPBLENDFUNCTION;


            The BLENDFUNCTION structure controls blending by specifying the blending functions for source and destination bitmaps.
            BLENDFUNCTION這種結(jié)構(gòu)的混合控制通過指定源和目標位圖的混合功能
            BlendOp

            The source blend operation. Currently, the only source and destination blend operation that has been defined is AC_SRC_OVER. For details, see the following Remarks section.

            指定源混合操作。目前,唯一的源和目標混合,已定義的AC_SRC_OVER; 即根據(jù)源alpha值把源圖像疊加到目標圖像上。OpenGLalpha混合還支持其他的方式,如常量顏色源。

            BlendFlags

            Must be zero.


            SourceConstantAlpha

            Specifies an alpha transparency value to be used on the entire source bitmap. The SourceConstantAlpha value is combined with any per-pixel alpha values in the source bitmap. If you set SourceConstantAlpha to 0, it is assumed that your image is transparent. Set the SourceConstantAlpha value to 255 (opaque) when you only want to use per-pixel alpha values.

            指定一個alpha透明度值將用于整個源位圖;該SourceConstantAlpha值與任何在源位圖的每個像素的alpha值組合;如果設(shè)置為0,就會假定你的圖片是透明的;如果需要使用每像素alpha值,設(shè)置SourceConstantAlpha值255(不透明);

            AlphaFormat

            This member controls the way the source and destination bitmaps are interpreted. AlphaFormat has the following value.

            Value Meaning
            AC_SRC_ALPHA This flag is set when the bitmap has an Alpha channel (that is, per-pixel alpha). Note that the APIs use premultiplied alpha, which means that the red, green and blue channel values in the bitmap must be premultiplied with the alpha channel value. For example, if the alpha channel value is x, the red, green and blue channels must be multiplied by x and divided by 0xff prior to the call.


              AlphaFormat 此成員控制源和目標位圖的解釋;看以下值:
              AC_SRC_ALPHA 這個標志被設(shè)置當那位圖有Alpha通道(也就是說,每個像素的Alpha);
              例如,如果Alpha通道值是x,紅色,綠色和藍色通道必須乘以x和由
              0xff分開在調(diào)用之前

            Remarks

            When the AlphaFormat member is AC_SRC_ALPHA, the source bitmap must be 32 bpp. If it is not, the AlphaBlend function will fail.

            When the BlendOp member is AC_SRC_OVER, the source bitmap is placed over the destination bitmap based on the alpha values of the source pixels.

            If the source bitmap has no per-pixel alpha value (that is, AC_SRC_ALPHA is not set), the SourceConstantAlpha value determines the blend of the source and destination bitmaps, as shown in the following table. Note that SCA is used for SourceConstantAlpha here. Also, SCA is divided by 255 because it has a value that ranges from 0 to 255.

            Dst.Red= Src.Red * (SCA/255.0)+ Dst.Red * (1.0 - (SCA/255.0))
            Dst.Green= Src.Green * (SCA/255.0)+ Dst.Green * (1.0 - (SCA/255.0))
            Dst.Blue= Src.Blue * (SCA/255.0)+ Dst.Blue * (1.0 - (SCA/255.0))

            ?

            If the destination bitmap has an alpha channel, then the blend is as follows.

            Dst.Alpha= Src.Alpha * (SCA/255.0)+ Dst.Alpha * (1.0 - (SCA/255.0))

            ?

            If the source bitmap does not use SourceConstantAlpha (that is, it equals 0xFF), the per-pixel alpha determines the blend of the source and destination bitmaps, as shown in the following table.

            Dst.Red= Src.Red+ (1 - Src.Alpha) * Dst.Red
            Dst.Green= Src.Green+ (1 - Src.Alpha) * Dst.Green
            Dst.Blue= Src.Blue+ (1 - Src.Alpha) * Dst.Blue

            ?

            If the destination bitmap has an alpha channel, then the blend is as follows.

            Dest.alpha= Src.Alpha+ (1 - SrcAlpha) * Dst.Alpha

            ?

            If the source has both the SourceConstantAlpha (that is, it is not 0xFF) and per-pixel alpha, the source is pre-multiplied by the SourceConstantAlpha and then the blend is based on the per-pixel alpha. The following tables show this. Note that SourceConstantAlpha is divided by 255 because it has a value that ranges from 0 to 255.

            Src.Red= Src.Red* SourceConstantAlpha / 255.0;
            Src.Green= Src.Green* SourceConstantAlpha / 255.0;
            Src.Blue= Src.Blue* SourceConstantAlpha / 255.0;
            Src.Alpha= Src.Alpha* SourceConstantAlpha / 255.0;
            Dst.Red= Src.Red+ (1 - Src.Alpha) * Dst.Red
            Dst.Green= Src.Green+ (1 - Src.Alpha) * Dst.Green
            Dst.Blue= Src.Blue+ (1 - Src.Alpha) * Dst.Blue
            Dst.Alpha= Src.Alpha+ (1 - Src.Alpha) * Dst.Alpha

            ?

            最后一個字段AlphaFormat有兩個選擇:0表示常量alpha值,AC_SRC_ALPHA表示每個像素有各自的alpha通道。

            如果AlphaFormat字段為0,源位圖中的所有像素使用同樣的常量alpha值,即SourceConstantAlpha字段中的值,該值實際上是0255,而不是01。這里0表示完全透明,255表示完全不透明。目標像素以255-SourceConstantAlpha值作為alpha值。

            如果AlphaFormat字段的值是AC_SRC_ALPHA,源設(shè)備表面的每個像素必須有各自的alpha通道。即,必須是32-bpp的物理設(shè)備上下文,或是選中了32-bpp DDBDIB段的內(nèi)存設(shè)備上下文。這些情況下,每個源像素有48位通道:紅、綠、藍和alpha。每個像素的alpha通道和SourceConstantAlpha字段一起用于把源和目標混合起來。實際用于計算的運算式如下:

            Tmp.Red ??= Src.Red ??* SourceConstantAlpha / 255;

            Tmp.Green = Src.Green * SourceConstantAlpha / 255;

            Tmp.Blue ?= Src.Blue ?* SourceConstantAlpha / 255;

            Tmp.Alpha = Src.Alpha * SourceConstantAlpha / 255;

            Beta????? = 255 – Tmp.alpha;

            Dst.Red ??= Tmp.Red? ?+ Round((Beta * Dst.Red? )/255);

            Dst.Green = Tmp.Green + Round((Beta * Dst.Green)/255);

            Dst.Blue ?= Tmp.Blue ?+ Round((Beta * Dst.Blue )/255);

            Dst.Alpha = Tmp.Alpha + Round((Beta * Dst.Alpha)/255);


            Feedback

            # re: BLENDFUNCTION   回復(fù)  更多評論   

            2012-08-09 09:16 by changmning
            有這個函數(shù)BLENDFUNCTION的用法實例嗎?
            成人精品一区二区久久| 欧美久久亚洲精品| 东京热TOKYO综合久久精品| 国产三级久久久精品麻豆三级| 久久婷婷国产综合精品| 一本一本久久a久久综合精品蜜桃| 97久久久久人妻精品专区 | 久久精品免费全国观看国产| 合区精品久久久中文字幕一区| 久久人人爽人人爽AV片| 久久久久久久波多野结衣高潮| 99久久国产综合精品女同图片| 久久久国产精品亚洲一区| 91秦先生久久久久久久| 久久国产欧美日韩精品| 久久免费香蕉视频| 久久国产亚洲精品无码| 一极黄色视频久久网站| 国产精品狼人久久久久影院 | 精品永久久福利一区二区| 久久狠狠高潮亚洲精品| 97久久国产综合精品女不卡| 久久狠狠一本精品综合网| 国产综合久久久久久鬼色| 久久人人爽人人爽人人片AV不| 91久久精品无码一区二区毛片| 亚洲午夜久久久久久久久电影网| 91麻豆精品国产91久久久久久| 人妻无码αv中文字幕久久琪琪布| 一本久久a久久精品综合夜夜 | 性欧美大战久久久久久久久| 久久久国产精品| 九九热久久免费视频| 99热精品久久只有精品| 一本伊大人香蕉久久网手机| 777久久精品一区二区三区无码| 久久水蜜桃亚洲av无码精品麻豆| 日韩十八禁一区二区久久| 国产成人99久久亚洲综合精品| 久久av无码专区亚洲av桃花岛| 国产精品美女久久福利网站|