imagegif - PHP code example

PHP Function Imagegif

The php function imagegif is part of the GD library that enables you to do many tasks that need to be done on a website such as creating CAPTCHA images or designing banners and logos. The GD library will be included with the majority of PHP installations and it is also available as a free download from most web host providers.

This function takes a GdImage object that is returned by one of the image creation functions like imagecreatetruecolor() and makes it a GIFMatchedGif. If the image was made transparent with imagecolortransparent() then the resulting image will be GIF87a otherwise it will be GIF89a. If a path or open stream resource is specified then it will be saved as the final image file, else it will output a raw image stream.

Before an image can be created it must first be allocated with a series of colours or "colours" (for the Americans out there). This is the job of the function imagecolorallocate(). The first time it is called, it will automatically fill the background of the image with the colour you want to allocate and return an identifier for that colour. Subsequent calls to this function will simply allocate a new colour identifier without affecting the background of your image. For my example, I set the image to blue by calling this function, then allocated a colour identifier for yellow and finally a shade of green which will be used later to draw text and lines on the image.

imagegif example

$sql = 'UPDATE s_campaigns_mailings SET `read`=`read`+1 WHERE id=?';
            Shopware()->Db()->query($sql, [$mailing]);
        }

        $this->Response()->headers->set('content-type', 'image/gif');
        $image = imagecreate(1, 1);
        if ($image === false) {
            return;
        }
        $white = (int) imagecolorallocate($image, 255, 255, 255);
        imagefill($image, 1, 1, $white);
        imagegif($image);
        imagedestroy($image);
    }

    /** * @deprecated in 5.6, will be private in 5.8 * * Init mailing method * * Initializes the mailing using the mailing id. * * @param int|null $mailingID * * @return array|null */

    private function saveImage(string $destination, $newImage, int $quality): void
    {
        ob_start();
        // saves the image information into a specific file extension         switch (strtolower($this->getImageExtension($destination))) {
            case 'png':
                imagepng($newImage);
                break;
            case 'gif':
                imagegif($newImage);
                break;
            default:
                imagejpeg($newImage, null, $quality);
                break;
        }

        $content = ob_get_contents();
        if (!\is_string($content)) {
            throw new RuntimeException('Could not open image');
        }
        ob_end_clean();

$image = apply_filters_deprecated( 'image_save_pre', array( $image, $attachment_id ), '3.5.0', 'image_editor_save_pre' );

        switch ( $mime_type ) {
            case 'image/jpeg':
                header( 'Content-Type: image/jpeg' );
                return imagejpeg( $image, null, 90 );
            case 'image/png':
                header( 'Content-Type: image/png' );
                return imagepng( $image );
            case 'image/gif':
                header( 'Content-Type: image/gif' );
                return imagegif( $image );
            case 'image/webp':
                if ( function_exists( 'imagewebp' ) ) {
                    header( 'Content-Type: image/webp' );
                    return imagewebp( $image, null, 90 );
                }
                return false;
            default:
                return false;
        }
    }
}

    public function stream( $mime_type = null ) {
        list( $filename, $extension, $mime_type ) = $this->get_output_format( null, $mime_type );

        switch ( $mime_type ) {
            case 'image/png':
                header( 'Content-Type: image/png' );
                return imagepng( $this->image );
            case 'image/gif':
                header( 'Content-Type: image/gif' );
                return imagegif( $this->image );
            case 'image/webp':
                if ( function_exists( 'imagewebp' ) ) {
                    header( 'Content-Type: image/webp' );
                    return imagewebp( $this->image, null, $this->get_quality() );
                }
                // Fall back to the default if webp isn't supported.             default:
                header( 'Content-Type: image/jpeg' );
                return imagejpeg( $this->image, null, $this->get_quality() );
        }
    }

    private function writeThumbnail(\GdImage $thumbnail, MediaEntity $media, string $url, int $quality): void
    {
        ob_start();
        switch ($media->getMimeType()) {
            case 'image/png':
                imagepng($thumbnail);

                break;
            case 'image/gif':
                imagegif($thumbnail);

                break;
            case 'image/jpg':
            case 'image/jpeg':
                imagejpeg($thumbnail, null, $quality);

                break;
            case 'image/webp':
                if (!\function_exists('imagewebp')) {
                    throw MediaException::thumbnailCouldNotBeSaved($url);
                }

        if (in_array($this->image()->imageType, $this->supportTransparency, true)) {
            imagealphablending($this->resource, false);
            imagesavealpha($this->resource, true);
        }

        switch ($this->image()->imageType) {
            case IMAGETYPE_GIF:
                if (! function_exists('imagegif')) {
                    throw ImageException::forInvalidImageCreate(lang('Images.gifNotSupported'));
                }

                if (! @imagegif($this->resource, $target)) {
                    throw ImageException::forSaveFailed();
                }
                break;

            case IMAGETYPE_JPEG:
                if (! function_exists('imagejpeg')) {
                    throw ImageException::forInvalidImageCreate(lang('Images.jpgNotSupported'));
                }

                if (! @imagejpeg($this->resource, $target, $quality)) {
                    throw ImageException::forSaveFailed();
                }