ios - CGBitmapContextCreate を使用した UIImage の描画 - テクスチャ用のフルサイズの画像 - iOS

Question

以下のコードを使用して UIImage を描画しています。いくつかの頂点を使用して、この場合は正方形を描画しています。

- (UIImage *)drawTexture : (NSArray *)verticesPassed {

    CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();

    CGContextRef con = CGBitmapContextCreate(NULL,
                                                               1000,
                                                               1000,
                                                               8,
                                                               0,
                                                               rgbColorSpace,
                                                               kCGImageAlphaPremultipliedFirst);

    CGColorSpaceRelease(rgbColorSpace);

    CGContextSetLineWidth(con, 10);

    Line * start = [verticesPassed objectAtIndex:0];
    StandPoint * startPoint = start.origin;

    CGContextMoveToPoint(con, [startPoint.x floatValue], [startPoint.y floatValue]);

    for (Line * vertice in verticesPassed) {
        StandPoint * origin = vertice.origin;
        CGContextAddLineToPoint(con, [origin.x floatValue], [origin.y floatValue]);
        NSLog(@"Texutre point is %f %f", [origin.x floatValue], [origin.y floatValue]);
    }

    CGContextSetFillColorWithColor(con, [UIColor greenColor].CGColor);

    CGContextFillPath(con);

    [self drawText:con startX:250 startY:200 withText:standName];
    [self drawText:con startX:250 startY:150 withText:standNumber];


    CGImageRef cgImage = CGBitmapContextCreateImage(con);

    UIImage *newImage = [[UIImage alloc]initWithCGImage:cgImage];

    NSLog(@"Size is %f", newImage.size.height);

    return newImage;

}

私の正方形の頂点は次のとおりです。

Texutre point is 667.000000 379.000000
Texutre point is 731.000000 379.000000
Texutre point is 731.000000 424.000000
Texutre point is 667.000000 424.000000

問題は、1000x1000 のコンテキストでは、明らかにコンテキストの右上に非常に小さな形状が描画されることです。

この UIImage をテクスチャとして使用したいので、空白なしで正しいサイズの形状を作成するにはどうすればよいですか (つまり、0,0 から始まります)。

Bugivore からのコード:

- (UIImage *)drawTexture : (NSArray *)verticesPassed {

    CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();

    //This function gets the bounds or smallest rectangle required to generate a shape which
    //will be used as pattern
    CGRect shp = [self boundFromFrame:verticesPassed];


    //Generate the shape as image so that we can make pattern out of it.
    CGContextRef conPattern = CGBitmapContextCreate(NULL,
                                                    shp.size.width,
                                                    shp.size.height,
                                                    8,
                                                    0,
                                                    rgbColorSpace,
                                                    (CGBitmapInfo)kCGImageAlphaPremultipliedFirst);

    CGColorSpaceRelease(rgbColorSpace);

    CGContextSetLineWidth(conPattern, 10);
    CGContextSetStrokeColorWithColor(conPattern, [UIColor blueColor].CGColor);

    Line * start = [verticesPassed objectAtIndex:0];
    StandPoint * startPoint = start.origin;
    CGContextMoveToPoint(conPattern, [startPoint.x floatValue]-shp.origin.x , [startPoint.y floatValue]-shp.origin.y);

    for (Line * vertice in verticesPassed) {
        StandPoint * standPoint = vertice.origin;
        CGContextAddLineToPoint(conPattern, [standPoint.x floatValue]-shp.origin.x, [standPoint.y floatValue]-shp.origin.y);
    }

    CGContextStrokePath(conPattern);

    //Make the main image and color it with pattern.
    CGImageRef cgImage = CGBitmapContextCreateImage(conPattern);

    UIImage *imgPattern = [[UIImage alloc]initWithCGImage:cgImage];
    //UIImageWriteToSavedPhotosAlbum(imgPattern, nil, nil, nil);


    UIColor *patternColor = [UIColor colorWithPatternImage:imgPattern];

    CGContextRef con = CGBitmapContextCreate(NULL,
                                             500,
                                             500,
                                             8,
                                             0,
                                             rgbColorSpace,
                                             (CGBitmapInfo)kCGImageAlphaPremultipliedFirst);

    CGColorSpaceRelease(rgbColorSpace);

    CGContextSetLineWidth(con, 10);

    CGContextMoveToPoint(con, 0 , 0);
    CGContextAddLineToPoint(con, 500 , 0 );
    CGContextAddLineToPoint(con, 500, 500 );
    CGContextAddLineToPoint(con, 0 , 500);


    CGContextSetFillColorWithColor(con, patternColor.CGColor);

    CGContextFillPath(con);


    CGImageRef cgImageFinal = CGBitmapContextCreateImage(con);

    UIImage *newImage = [[UIImage alloc]initWithCGImage:cgImageFinal];

    UIImageWriteToSavedPhotosAlbum(newImage, nil, nil, nil);

    return newImage;


}
-(CGRect)boundFromFrame:(NSArray*)verticesPassed
{
    float top,left,right,bottom;
    bool bFirst = YES;

    for (Line * vertice in verticesPassed) {
        StandPoint * standPoint = vertice.origin;
        if(bFirst)
        {
            left = right = [standPoint.x floatValue];
            top = bottom = [standPoint.y floatValue];
            bFirst = NO;
        }
        else{
            if ([standPoint.x floatValue]<left) left = [standPoint.x floatValue];
            if ([standPoint.x floatValue]>right) right = [standPoint.x floatValue];
            if ([standPoint.x floatValue]<top) top = [standPoint.y floatValue];
            if ([standPoint.x floatValue]>bottom) bottom = [standPoint.y floatValue];
        }

    }

    return CGRectMake(left, top, right - left, bottom-top);

}

フォトアルバムで :

ここに画像の説明を入力

score 1 · Accepted Answer

テストのためにコードを少し変更したことに注意してください。しかし、これは配列座標を取り、線座標に基づいて形状を描画します。はその形状を使用して、1000x1000 の画像にパターンを描画します。コードをテストできるように、最終的な画像はフォトアルバムに保存されます。元のコードに従って UIImage の戻り値に置き換えることができます。ただし、これは主に、図面を使用してテクスチャを作成する方法を示しています。

- (void)drawTexture : (NSArray *)verticesPassed {

CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();

//This function gets the bounds or smallest rectangle required to generate a shape which
//will be used as pattern
CGRect shp = [self boundFromFrame:verticesPassed];


//Generate the shape as image so that we can make pattern out of it.
CGContextRef conPattern = CGBitmapContextCreate(NULL,
                                         shp.size.width,
                                         shp.size.height,
                                         8,
                                         0,
                                         rgbColorSpace,
                                         kCGImageAlphaPremultipliedFirst);

CGColorSpaceRelease(rgbColorSpace);

CGContextSetLineWidth(conPattern, 10);
CGContextSetStrokeColorWithColor(conPattern, [UIColor blueColor].CGColor);

Line * start = [verticesPassed objectAtIndex:0];
CGContextMoveToPoint(conPattern, start.x-shp.origin.x , start.y-shp.origin.y);

for (Line * vertice in verticesPassed) {
    CGContextAddLineToPoint(conPattern, vertice.x-shp.origin.x , vertice.y-shp.origin.y );
}
CGContextStrokePath(conPattern);

//Make the main image and color it with pattern.
CGImageRef cgImage = CGBitmapContextCreateImage(conPattern);

UIImage *imgPattern = [[UIImage alloc]initWithCGImage:cgImage];
//UIImageWriteToSavedPhotosAlbum(imgPattern, nil, nil, nil);


UIColor *patternColor = [UIColor colorWithPatternImage:imgPattern];

CGContextRef con = CGBitmapContextCreate(NULL,
                                         1000,
                                         1000,
                                         8,
                                         0,
                                         rgbColorSpace,
                                         kCGImageAlphaPremultipliedFirst);

CGColorSpaceRelease(rgbColorSpace);

CGContextSetLineWidth(con, 10);



CGContextMoveToPoint(con, 0 , 0);
CGContextAddLineToPoint(con, 1000 , 0 );
CGContextAddLineToPoint(con, 1000 , 1000 );
CGContextAddLineToPoint(con, 0 , 10000 );


CGContextSetFillColorWithColor(con, patternColor.CGColor);

CGContextFillPath(con);


CGImageRef cgImageFinal = CGBitmapContextCreateImage(con);

UIImage *newImage = [[UIImage alloc]initWithCGImage:cgImageFinal];

UIImageWriteToSavedPhotosAlbum(newImage, nil, nil, nil);


}
-(CGRect)boundFromFrame:(NSArray*)verticesPassed
{
float top,left,right,bottom;
bool bFirst = YES;

for (Line * vertice in verticesPassed) {
    if(bFirst)
    {
        left = right = vertice.x;
        top = bottom = vertice.y;
        bFirst = NO;
    }
    else{
        if (vertice.x<left) left = vertice.x;
        if (vertice.x>right) right = vertice.x;
        if (vertice.x<top) top = vertice.y;
        if (vertice.x>bottom) bottom = vertice.y;
    }

}

return CGRectMake(left, top, right - left, bottom-top);

}

ios - CGBitmapContextCreate を使用した UIImage の描画 - テクスチャ用のフルサイズの画像 - iOS

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