This is a convenience for annotating an image with text. >-matte operation was the same as " -alpha Note that while the obsolete +matte operation was the PNG, smaller as the RGB values of transparent pixels are more uniform, This can make some image file formats, such as Set any fully-transparent pixel to the background color, while leaving That is the RGB color channels isĬomposite the image over the background color. ShapeĪs per 'Copy' but also colors the resulting shape mask with Grayscale intensity of the image, into the alpha channel, convertingĪ grayscale mask into a transparent shaped mask ready to be coloredĪppropriately. Turns 'On' the alpha/matte channel, then copies the 'Off' the image's transparency, so as to generateĪ grayscale mask of the image's shape. Same size as the original and with all its original RGB data stillĬopies the alpha channel values into all the color channels and turns This effectively creates a fully transparent image the OpaqueĮnables the alpha/matte channel and forces it to be fully opaque.Īctivates the alpha/matte channel and forces it to be fully The alpha channel turned on, it will have no effect. Then it also resets the channel to opaque. Disassociateĭisassociate the alpha channel from the image. Does not delete or change theĮxisting data, just turns off the use of that data. Deactivateĭisables the image's transparency channel. Preserve existing (but specifically turned Off) transparencyĪssociate the alpha channel with the image. Should be used instead of this, unless you specifically need to Matrix determinant has a sufficiently small absolute value it is rejected.Įnable the image's transparency channel. Transformations can be accomplished by instead by a single -affine operation using the matrix equal to the product of the matricesĪn attempt is made to detect near-singular transformation matrices. The cumulative effect of a sequence of -affine Rotate clockwise about the origin (the upper left-hand corner) by an angle Translation by a displacement ( t x, t y) is accomplished like so: -affine 1,0,0,1, t x, t y See -transform, and the -distort method ' Affineprojection for more Respectively, is accomplished with the following. Therefore,įour parameters suffice for rotation and scaling without translation. The transformation matrix complies with the left-handed pixel coordinateĪre rightward and downward, resp. Subsequently shift the image pixels so that those that are moved out of the The size of the resulting image is that of the smallest rectangle thatĬontains the transformed source image. Image are calculated using the following matrix equation. Internally, the transformation matrix has 3x3 elements, but three of themĪre omitted from the input because they are constant. The matrix entries are entered as comma-separated numeric values either in This option sets a transformation matrix, for use by subsequent -draw or -transform options. Set the drawing transformation matrix for combined rotating and scaling.
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